VITAE

Raytcho D. Lazarov
Department of Mathematics
Texas A&M University
College Station, TX 77845, USA

Citizenship: USA and Bulgaria

Marital Status: Married with two children

Education:

1. M.Sci. (mathemaics), The Wroclaw University, Poland, 1966
2. Ph.D. (physics and mathematics), The Moscow State University, USSR, 1972
3. Dr.Sci. (applied mathematics), The Sofia University, Bulgaria, 1982

Professional Experience:

1. Mathematician, Institute of Mathematics, Bulgarian Academy of Sciences (BAS), 1966-68
2. Postgraduate student, Moscow State University, 1968-71
3. Research associate, Institute of Mathematics, Bulgarian Academy of Sciences, 1972-79
4. Research associate, Rutherford Laboratory, Didcot, UK, 1976 (1 year)
5. Senior researcher, Insttute of Mathematics, BAS, 1979-86
6. Senior researcher, Joint Institute for Nuclear Research, Dubna, USSR, 1980 (Fall semester)
7. Head of Laboratory on Numerical Analysis, BAS, 1985-1991
8. Deputy-Director, Laboratory on Parallel Algorithms and High Performance Computer Systems, BAS, 1985-1988
9. Professor of Mathematics, Institute of Mathematics, BAS, 1986-present.
10. Deputy-Director of Center for Informatics and Computer Technology, BAS, 1986-1988
11. Visiting Professor, University of Wyoming, USA, 1987 (1 year)
12. Visiting Fellow, Australian National University,Canberra,1990, (2 months)
13. Professor of Mathematics, University of Wyoming, Laramie, USA, 1991-1993
14. Visiting Fellow, Mittag Leffler Institute of Mathematics, Stockholm, Sweden, 1998, (1 month)
15. Professor of Mathematics, Texas A&M University, College Station, USA, 1992-present
16. Visiting Professor, University of Linz and RICAM, Austria, 2005 (2 months)
17. Visiting Fellow, Fraunhofer Institute of Industrial Mathematics, Kaiserslautern, Germany, 2006, (6 months)
18. Visiting Professor, University of Sofia, Bulgaria, 2006 (2 months)
19. Visiting Professor, University of Kaiserslautern, supported by Erasmus Mundus program within the European School for Industrial Mathematics (EISM), 2008 - 2011

Professional Societies:

1. American Mathematical Society
2. GAMM (Gieselschaft fur Angewandte Mathematik und Mechanik)
3. SIAM
4. International Linear Algebra Society

Boards, Councils and Committees:

1. Scientific council of the Institute of Mathematics-1989- 1991
2. Scientific council of the Institute of Mechanics and Biomechanics (1989 for 5 months)
3. Council on Mathematics, National Supreme Commission for Attestation, confering degrees in Ph.D., Member 1985-1990
4. Council on Mathematics, National Supreme Commission for Attestation, confering degrees in Ph.D., Chairman 1990-1991
5. Working Group WG 2.5, International Federation for Information Processing, Member, 1988-present
6. Supreme Commission for Attestation, Section on Physics and Mathematics, Member 1982-1984, Vice-chairman 1985-1989
7. Supreme Commission for Attestation, Mathematical Section, Vice-chairman 1990-1991

Editorial Work:

1. Proceedings International Conference on Numerical Methods and Applications, Sofia 1984, Editor.
2. Optimal algorithms, Proc. Int. Conf. on Optimal Algorithms, Blagoevgrad, 1987, Co-editor.
3. Proceedings, International Conference on Numerical Methods and Applications, Sofia, 1988, Editor.
4. Proceedings of the Int. Conference on Integral Equations and Inverse Problems, Varna, 1989, Longman, London, Editor.
5. Numerical Methods for Partial Differential Equations, John Wiley and Sons, Member of the Editorial Board, 1990 - present.
6. East-West Journal on Numerical Mathematics, (currently J. Numer. Math.) Member of the Editorial Board, 1992-present.
7. Mathematical Modeling and Computational Experiment, An International Journal, 1995 - 1997.
8. SIAM Journal on Numerical Analysis, Member of the Editorial Board, 1999-2004
9. Computational Methods in Applied Mathematics, Editor, 2000-present.

Recognition/Awards:

1. The medal "St. Kl. Ohridski" with blue ribbon (the highest honors given by Sofia University, Bulgaria, to scientists), 2003
2. Doctor Honoris Causa of Sofia University "St. Kl. Ohridski", Bulgaria, 2006
3. The medal of the Institute of Mathematics, Bulgarian Academy of Sciences, 2008
4. Pichoridis Distiguished Lectureship, University of Crete, Greece, June 2008
5. Erasmus Mundus Visiting Scholar Award, University of Kaiserslautern, July 2008 - June 2011

Publications :

1. R.D. Lazarov, Difference schemes for the second boundary value problem of elasticity for domains with curved boundaries, USSR J. Comp. Math. and Math. Physics, v.11 (4) (1971), 166-179.
2. R.D. Lazarov, Variational-difference schemes for axisymmetric problems of elasticity, Seminar of the Inst. Appl. Math., Georgian State Univ., 5 (1971), 77-83 (Russian).
3. R.D. Lazarov, Difference schemes for problems of elasticity in domains with curvilinear boundaries. I. Construction of the difference scheme. A priori estimate. Theoretical and Appl. Mech., v.2 (4) (1972), 19-30 (Russian)
4. R.D. Lazarov, Difference schemes for problems of elasticity in domains with curvilinear boundaries. II. Error estimate. Numerical experiments, Theoretical and Appl. Mech., v.4 (2) (1973), 133-124 (Russian)
5. R.D. Lazarov and E. Varbanova Difference scheme for a mixed elastic problem in an orthotropic cylinder, Proc. Sec. Nat. Congress Theoretical and Appl. Mech., Varna,1973, v.2 (1976), 235-243 (Russian)
6. R.D. Lazarov, Difference methods and their application to the problems of elasticity, Math. and Math. Education, Proc. Second Conf. Union Bulgarian Math., 1973, 143-150 (Russian), Zb # 366.73011
7. R.D. Lazarov and Yu.I. Mokin, On the stability of elliptic difference schemes, USSR J. Comput. Math. and Math. Physics, v.13 (2) (1973), 282-291 (Russian), Zb # 432.73079
8. R.D. Lazarov and Yu.I. Mokin, Stability of elliptic difference schemes in Lp-metrics, Issl. Teorii Raznostn. Schem Ellipt. Parabol. Uravn., Moscow State Univ. Publishers (1973), 40-88 (Russian)
9. R.D. Lazarov and E. Varbanova Numerical solution to mixed boundary value problems of elasticity in orthotropic cylinders, Ann. VUZ, Appl. Math., v.10 (4) (1974) (Bulgarian),Zb# 343.73011
10. R.D. Lazarov, E.P. Zhidkov, M.S. Kaschiev, Computing three-dimensional electrostatic fields for rectangular electrodes, Comm. JINR, Dubna, 9-9181 (1975) (Russian)
11. Chr. Butzev, A. Hachikian, and R.D. Lazarov, On calculation of axially-symmetric electric fields, Ann. Ecole Superieur de Mines et de Geologie, v.21 (1) (1975), 133-140 (Bulgarian)
12. R.D. Lazarov, Difference schemes for solving problems of elastic equilibrium of isotropic cylinder, Cisl. Analys, Inst. of Cybern. of Ukrain. Acad. of Sciences, 1975, 3-19 (Russian)
13. R.D. Lazarov, A factored scheme for an axially-symmetric dynamic problem of elasticity, Ann. VIZ, Appl. Mathematics, v.11 (2) (1975), 103-112 (Russian), Zb# 395.73076
14. R.D. Lazarov and M.S. Kaschiev, Numerical solution to some 3-D electrostatic problems, modelling accelerating cameras, Math. and Math. Education, Proc. Fourth Conf. Union Bulgarian Mathematicians, 1975, 221-226 (Bulgarian)
15. R.D. Lazarov and P.Panayotov, Solving an axially-symmetric elastic problem by projection difference method, Ann. VUZ, Applied Mathematics, v.12 (2) (1976) (Bulgarian), Zb# 432.73080
16. P. Gospodinov, G. Saev, and R. Lazarov, Computing transient temperature fields by the finite element method, Mashinostroenie, v.1 (1976), 23-26 (Bulgarian)
17. R.D. Lazarov and L.Stoyanov, Difference schemes for mixed boundary value problems of elasticity on triangular grids, Comm. VMEI Gabrovo, v.8 (1976), 53-62 (Bulgarian)
18. R.D. Lazarov, Difference schemes of second order accuracy for the axisymmetric problems of elasticity in a cylinder, Comptes Rend. de l'Acad. Bulg. Sci., v.29 (1976), 21-24 (Russian), Zb# 366.73011
19. R.D. Lazarov and V.M. Petkov, Economical difference scheme for a mixed boundary value problem of Neuman type for hyperbolic equations of second order, Math. and Math. Education, Proc. Third Conf. Union Bulgarian Mathematicians, 1976, 209-215 (Bulgarian), Zb # 355.65075
20. R.D. Lazarov and G. Meladze, On the application of difference schemes for solving the problem of a vibrating elastic strip, Bull. Acad. Sci. Georgian SSR, v.83 (1976), 17-21 (Russian)
21. R.D. Lazarov, Factorized finite difference schemes of second order accuracy for solving dynamic problems of elasticity, Comptes Rend. de l'Acad. Bulg. Sci., v.32 (1979), 1, 7-10 (Russian), Zb # 432.73079 MR# 80f:65133
22. K. Ganev and R.D. Lazarov, An application of the splitting method for solving some problems of mesometeorology, Bulgarian Geophysical J., v. 5 (1979), 11-21 (Russian)
23. R.D. Lazarov and G. Meladze, Factorized schemes for the dynamic problems of elastic vibrations of an unbounded strip, Trudy Tbilissi State University, v.207 (1979), 14-26 (Russian), Zb # 462.73038
24. M.S. Kaschev and R.D. Lazarov, Numerical solution of the two-dimensional Schrodinger equation corresponding to a two-center problem, Comm. JINR, Dubna, P11-12307 (1979) (Russian)
25. R.D. Lazarov and S.D. Margenov, An application of parabolic and cubic splines to solution of fourth order elliptic boundary value problems on a rectangle, Preprint N 64, Seminar on Methods of Comput. and Appl. Mathematics, Siberian Branch Acad. Sci. of USSR, 1979 (Russian).
26. R.D. Lazarov and E. Varbanova, Difference schemes for 1-D coupled dynamic problems of thermoelasticity, Ann. VUZ Appl. Math., v.16 (4) (1980), 167-178, (Russian), MR # 83d:73080a, Zb# 497.73004
27. R.D. Lazarov, On the convergence of the difference schemes for axially symmetric problems of elasticity, Comm. JINR, Dubna, P11-80-884 (1980), 1-22 (Russian)
28. Mathematical models of cristalization of block of nitrogen steel, casted in cylindrical forms, Material Sci. and Technology, v.9 (1980), 63-68 (with I.Dimov et all., Bulgarian)
29. R.D. Lazarov and E. Varbanova, Numerical solution of a coupled problem of elasticity, Ann. VUZ, Appl. Math., v.16(4) (1980), 179-191 (Bulgarian), MR # 83d:73080b, Zb# 497.73005
30. R.D. Lazarov and E. Varbanova, Self similar solutions of the coupled thermoelasticity, Comm. JINR, Dubna, P5-80-886 (1980) (Russian)
31. I. Dimov,Tz. Rashev, V. Manolov, N. Andreev, Bl. Sendov, S. Domova, R.Lazarov, and T. Chernogorova, Mathematical modelling of heat conduction in ingot casting of stainless steel, Metallurgy, v.36 (1981),3-5 (Russian)
32. K. Gergiev and R.D. Lazarov, An error estimate for the decomposed finite element solution of the polyharmonic equation, Mathematics - Revue d'Analyse Numerique et de Theorie d'Approximation, v.23 (1981), 31-34 (K.Georgiev), MR#83g:65106, Zb #477.57015
33. R.D. Lazarov, On the convergence of the difference schemes for Poisson equation with generalized solutions, Diff. Equations, v.17 (7) (1981), 829-836, MR #83f:65169, Zb #485.65067
34. R.D. Lazarov, Convergence of finite difference schemes on generalized solutions of the biharmonic equation on a rectangle, Diff. Equations, v.17 (7) (1981), 836-842, MR #83h:65116, Zb #485.65068
35. R.D. Lazarov, Error estimate for the finite difference schemes for generalized solutions of the first boundary value axially symmetric elastic problems, Methods of Appr. and Interpolation, Ed. Yu. Kuznetsov, Acad. Sci. of USSR, Novosibirsk, 1981, 89-101, MR#87b:65175
36. S. Borshoukova and R.D. Lazarov, Package of computer programs for solving the basic 2-D problems of elasticity, Comm. JINR, Dubna, P11-81-149 (1981) (Russian)
37. P. Gospodinov, R.D. Lazarov, and S. Radev, Numerical treatment of some problems of fluid flow and instability of liquid jets, Meth. und Verfahren der Math. Physik, Proc. Conf. on Math. in Fluid Mechanics, Obervolfach (1981), Zb #562.76042
38. R.D. Lazarov and V.L. Makarov, Convergence of the difference methods and the methods of lines for multidimensional problems in classes of generalized solutions, Soviet Math. Dokl., v.23 (1981), 69-73, MR #83a:35004, Zb #485.65069
39. R.D. Lazarov, On the convergence of the difference schemes for some axisymmetric problems of mathematical physics in classes of generalized solutions, Soviet Math. Dokl., v.23 (1981), 667-670 MR#83h: 65115, Zb #524.65065
40. R.D. Lazarov and V.L. Makarov, Difference schemes of second order of accuracy for the axisymmetric Poisson equation with generalized solutions, USSR J. Comput. Math. and Math. Phys, v.21(5) (1981), 95-107, MR #84b:65100, Zb #485.65066
41. R.D. Lazarov and Yu.I. Mokin, On the convergence of the difference schemes for Poisson equation in L_p-metrics, Soviet Math. Dokl., v.24 (1981), 590-594, MR #83d:65272, Zb #524.65066
42. S.N. Dimova and R.D. Lazarov, Numerical methods for some heat problems, Cisl. Modeli, Analit. i Cisl. Metodi v Teorii Perenosa, Ed. A.Samarskii, Minsk, ITMO (1982), 55-73 (Russian)
43. R.D. Lazarov, On the convergence of the finite difference schemes for Poisson equation in discrete H^1-norms, p=2, Wiss. Beitr. IH Wismar, v.7 (1982), 86-90
44. R.D. Lazarov, Error estimates of the finite difference schemes for parabolic problems on generalized solutions, Comptes Rend. l'Acad. Bulg. Sci., v.35(1) (1982), 7-10 (Russian), MR #84a:65081 Zb #524.65067
45. R.D. Lazarov, Convergence of difference method for parabolic equations with generalized solutions, Pliska, v.5 (1982), 51-59 (Russian), MR #84m:65105, Zb #563.65063
46. I. Dimov,Tz. Rashev, V. Manolov, N. Andreev, Bl. Sendov, S. Dimova, R.Lazarov, and T. Chernogorova, Mathematical modelling of crystalization of steel blocks, Trudy Inst. of Metallurgy, v.14(1) (1983), 93-102 (Bulgarian)
47. R.D. Lazarov, On the numerical solution of some axially-symmetric elastic problems by finite difference method, Diff. Equations, v.19(3) (1983), 500-507 (Russian), MR #84f:65076, Zb#534.73066
48. R.D. Lazarov and Yu.I. Mokin, On the computation of the logarithmic potential, Soviet Math. Dokl., v.28 (1983), 320-323, MR #86d:31008, Zb #567.65070
49. R.D. Lazarov, V.L. Makarov, and W. Weinelt, On the convergence of difference schemes for elliptic equations with mixed derivatives and generalized solutions, Diff. Equations, v.19(7) (1983), 838-843, MR #85a:65153, Zb #547.65069
50. I. Gavriliuk, R. Lazarov, V. Makarov, and S. Pirnazarov, Error estimates for difference schemes for the second boundary value problem of biharmonic equation with minimal requirements of smoothness, Dop. Acad. Sci. Ukrain. SSR, ser. A, 2 (1983), 6-9 (Ukrainian), MR #85j:65039 Zb #541.65063
51. R.D. Lazarov, V.L. Makarov, and A.A. Samarskii, Application of exact difference schemes to the construction and study of difference schemes for generalized solutions, Math. USSR Sbornik, v.45(4) (1983), 461-171, MR #84g:65137, Zb #512.65068
52. I. Gavriliuk, R. Lazarov, V. Makarov, and S. Pirnazarov, Estimates of the rate of convergence of difference schemes for fourth order elliptic equations, USSR J. Comput. Math. and Math. Physics, v.23(2) (1983), 64-70, MR #85g:65115, Zb#541.65064
53. S.N. Dimova, N. Drenska, and R.D. Lazarov, Mathematical modelling of heat transfer in ingot cristalization, Comput. Math. Banach Center Publ., v.13 (1984), 73-90 (Russian)
54. R.D. Lazarov, V.L. Makarov, and W. Weinelt, On the convergence of difference schemes for the approximation of solutions u from W^m (m>0.5) of elliptic equations with mixed derivatives, Numer. Math., v.44 (1984), 223-232, MR #86f:65181,Zb #525.65069
55. A.B. Andreev, M.El Hatri, and R.D. Lazarov, Superconvergence of the gradient in the finite element method for some elliptic and parabolic problems, Variational-Difference Methods, Moscow, 1984, 13-25, Zb#605.65069
56. K.N. Godev and R.D. Lazarov, Error estimates of finite difference schemes in L_p-metrics for parabolic boundary value problems, Comptes Rend. l'Acad. Bulg. Sci., v.37 (1984), 565-568, Zb #567.65069, MR#86e:65137
57. R.D. Lazarov, W. Weinelt and U. Streit, On the convergence order of difference schemes for weak solutions of the heat equation, Diff. Equations, v.20(7) (1984) (Russian), MR #86b:65105, Zb # 554. 65068
58. S.N. Dimova, A. Jotova and R.D. Lazarov, Finite element package TERMO for solving heat problems, Numer. Meth. and Packages for Solving Problems of Math. Phys., Comput. Center Acad. Sci. USSR, Novosibirsk, 1985, 31-41 (Russian)
59. R.D. Lazarov and P.I. Shopov, A package for solving Stokes equations using finite elements with condensation, Proc. of Conf. on Numer. Meth. and Appl.'84, Sofia, 1985, 552-558 (Russian)
60. K.N. Godev and R.D. Lazarov, Convergence of difference schemes for elliptic problems with variable coefficients, Proc. Conf. on Numer. Meth. and Appl.'84, Sofia, 1985, 308-313
61. K.N. Godev and R.D. Lazarov, On the convergence of the difference scheme for the second boundary value problem for the biharmonic equation with solution from W^m , Math. Models in Phys. Chem. and Numerical Methods of Their Realization, Teubner-texte zur Math., v.61 (1985), 130-141, MR#87b:65175, Zb #542.65054
62. V. Kantchev and R.D. Lazarov, Superconvergence of the gradient of linear finite elements for 3-D Poisson equation, Optimal Algorithms, Sofia, 1986, 172- 182, Zb#672.65088
63. N. Andreev, V. Manolov, Tz. Rashev, T. Andreev, T. Tchernogorova, A. Jotova, S. Dimova, R. Lazarov, and G. Simeonov, Numerical simulation of some technology problems in metallurgy, Math. Models Analytic and Numer. Methods in Heat Transfer, v.2 (1986), Acad. Sci. Belorus.SSR, 106-114 (Russian)
64. R.D. Lazarov and V.L. Makarov, Difference schemes of second order accuracy for the axially symmetric Poisson equation on generalized solutions, Soviet Math. Dokl., v.25 (1982), 15-19, MR #83h:65114, Zb#488.65041
65. R.D. Lazarov, Superconvergence of the gradient for triangular and tetrahedral finite elements for solving linear problems of elasticity, Comput. Meth. and Systems, Nauka, Moscow, v. 6 (1988) 143-153 (Russian), Zb#694.73023
66. S.N. Dimova and R.D. Lazarov, Study of some physical processes by means of the numerical experiment, Summer School of Computer Appl. in Sci., Varna, 1986, 25-36 (Bulgarian)
67. R.D. Lazarov and P. Peykov, Modelling and investigation by simulation of semiconductor pressure sensors, Bulg. J. Physics, v.14(6) (1987), 530-541
68. K.N. Godev and R.D. Lazarov, Error estimates of finite difference schemes for parabolic equations with generalized solutions, Ann. de l'Universite de Sofia "Kl. Ohridski", Fac. de Math., v.79(1) (1985),403-413
69. R.D. Lazarov and V. Pasheva, Boundary element method for 2-D problems of ideal fluid flows with free boundaries, Adv. Water Resources, v.12 (1989), 37-45
70. R.E. Ewing and R.D. Lazarov, Local refinement techniques in the finite element and the finite difference methods, ISC Report #1988-14, Proc. Conf. on Numerical Methods and Appl.'88, Sofia, 1989, 148-159
71. R.E. Ewing, R.D. Lazarov, and P.S. Vassilevski, Local refinement techniques for elliptic problems on cell-centered grids, ISC, University of Wyoming, Preprint 1988-16 (1988), 1-73
72. R.E. Ewing and R.D. Lazarov, Adaptive local grid refinement, SPE 17806, presented at the Rocky Mountain Meeting, Casper, Wyoming, May 11-13,1988, 643-651
73. A.B. Andreev and R.D. Lazarov, Lumped mass finite element method for parabolic and eigenvalue problems, Mathematika Balkanica, New Series, v.2(1) (1988),84-92, Zb#000.65108
74. A.B. Andreev and R.D. Lazarov, Superconvergence of the gradient for quadratic triangular finite elements, Numerical Methods for Partial Diff. Equations, v.4(1) (1988), 15-32, Zb#644.65082
75. K.N. Godev, R.D. Lazarov, V.L. Makarov, and A.A. Samarskii, Homogeneous difference schemes for one dimensional problems with generalized solutions, Math. USSR Sbornik, v.59(1) (1988), 155-179, MR#88h:65145, Zb#621.65094
76. K.N. Godev and R.D. Lazarov, Truncated finite difference schemes for second boundary value problems for ordinary differential equations, Proc. Conference on Diff. Equations'85, Russe, Bulgaria, 1987, 675-682, MR#88k:65070
77. P.S. Vassilevski, R.D.Lazarov, and S.D. Margenov, Solving elliptic problems by the domain decomposition method using preconditioning matrices by multilevel splitting of the finite element matrix, Proc. Int.Conf. on Supercomputing, Athens, Lecture Notes in Computer Sci., v. 297 (1988), 826-835, MR#89b:65270
78. S. Chow and R.D. Lazarov, Superconvergence analysis of flux computations for nonlinear two-point boundary value problems, Preprint CMA-R09-88, Australian Nat. University (1988) and Bull.Austr.Math.Soc., v.40 (1989), 465-480, Zb#676.65096
79. A. Pehlivanov, G.F. Carey, S.S.Show, and R.D. Lazarov, Superconvergence analysis of the approximate boundary-flux calculations, Numer. Math., v. 63 (1992), 483-501
80. P.S. Vassilevski, R.D.Lazarov, and S.D. Margenov, Vector and parallel algorithms in iteration methods for elliptic problems, Math. and Math. Education, Proc. 18th Conf. of Union of Bulg. Mathematicians, 1989, 40-51
81. R.E. Ewing, R.D. Lazarov, J.E. Pasciak, and P.S. Vassilevski, Finite element methods for parabolic problems with time steps variable in space, Preprint #1989-05, 1989, ISC University of Wyoming
82. R.E. Ewing, R.D. Lazarov, and P.S. Vassilevski, Local refinement techniques for elliptic problems on cell centered grids. I. Error analysis, Preprint #1989-31, ISC, University of Wyoming, 1989, and Math. Comp., v. 56, (1991), N 194, 437-461
83. R.E. Ewing, R.D. Lazarov, and P.S. Vassilevski, Local refinement techniques for elliptic problems on cell centered grids. II. Two-grid iterative methods, Preprint #1989-47, ISC Univ. of Wyoming, 1989, J. Numerical Linear Algebra and Applications, v. 1 (4) (1994), 337-368
84. R.E. Ewing, R.D. Lazarov, and P.S. Vassilevski, Local refinement techniques for elliptic problems on cell centered grids. III. Algebraic multilevel BEPS preconditioners, Bulgarian Acad. Sci., CICT, Technical Report 6, 1989, and Numer. Mathematik, v. 58 (1991), 5, 431-452
85. R.D. Lazarov, V. Manolov, A. Yotova, and Tz. Rashev, Investigation of temperature fields of steel metallurgical blocks by the finite element method, Comptes Rend. l'Acad. Bulg. Sci., v.42 (1989), 4, 51-54
86. R.D. Lazarov, Local superconvergence analysis of the approximate boundary- flux calculations. Proc. of EQUADIFF'6 Conference, Prague,1989 Teubner-texte zur Mathematik, band 118, Leipzig, 1990, 275-278.
87. R. Ewing, R. Lazarov, T. Russell, and P. Vassilevski, Local refinement via domain decomposition techniques for the mixed finite element method, Third Int. Symposium on Domain Decomposition Methods for PDE's (Houston, 1989), Eds. T.Chan, R.Glowinski, J.Periaux and O.Widlund, SIAM, Philadelphia, 1990, 98-114
88. S. Dimova, R. Lazarov, Bl. Sendov, and Tz. Rashev, Mathematical modelling of some heat transfer processes in the steel casting industry, Proc. of Int. Conf. on High Nitrogen Steels, Varna, Sept 12-18, 1989, 178-184
89. R. Ewing, R. Lazarov, P. Lu, and P. Vassilevski, Preconditioning of indefinite systems arising from mixed finite element discretization of second order elliptic problems, Preconditioned Conjugate Gradient Methods, Eds O.Axelsson, L.Kolotilina, Lecture Notes in Math., v. 1457, 1990, 28-43
90. R. Ewing, R. Lazarov, and P. Vassilevski, Finite difference schemes on grids with local refinement in time and in space for parabolic problems.I.Derivation, stability and error analysis, Computing, v.45, 1990, 193-215
91. R. Ewing, R. Lazarov, and P. Vassilevski, Finite difference schemes on grids with local refinement in time and in space for parabolic problems.II. Optimal order two-grid iterative methods. Notes on Numerical Fluid Mechanics, W.Hackbusch (Ed.) v.25 (1990), 70-93
92. S. Chow, G. Carey, and R.D. Lazarov, Natural and postprocessed superconvergence in semi-linear problems, Numer. Methods for Partial Diff. Equations, v.7, (1991) 4, 245-259
93. R.D. Lazarov and A.I. Pehlivanov, Local superconvergence analysis of 3-D linear finite elements for boundary flux-calculations, The Mathematics of Finite Elements and Applications VII, MAFELAP 1990, J.R.Whiteman Ed., Academic Press, 1991, 65-74
94. R.E. Ewing, R.D. Lazarov, and P.S. Vassilevski, Mixed finite element solution of second order elliptic problems on grids with regular local refinement, Proc. Fourth Int. Conference on Domain Decomposition Methods for PDE's, R.Glowinski et all, Eds, SIAM, Philadelphia, 1991, 206-212
95. R.E. Ewing, R.D. Lazarov, and J. Wang, Superconvergence of the velocity along the Gauss lines in the mixed finite element methods, SIAM J. Numer. Anal., v.28, (1991), 4, 1015-1029
96. P.S. Vassilevski, R.D. Lazarov, and S.I. Petrova, Finite difference schemes on triangular cell-centered grids with local refinement, SIAM J. Statistical and Scientific Computation, v. 13, (1992), N6, 1287-1313
97. R.E. Ewing and R.D. Lazarov, Superconvergence of the mixed finite element approximations of parabolic problems using rectangular finite elements, East-West J. Numer. Mathematics, v.1, 1993, N3, 199-212. MR# 94m:65158
98. A.I. Pehlivanov, G. Carey, R.D. Lazarov, and Y. Shen, Convergence analysis of the least-square mixed finite elements Computing, v. 51, 1993, 111-123. MR# 95b:65096
99. R.E. Ewing, R.D. Lazarov, and A. Vassilev, Adaptive techniques for time-dependent problems, Comp. Meth.Appl. Mech. and Eng., v. 101, 1992, N 3, 113-126
100. R.E. Ewing, J.E. Pasciak, R.D. Lazarov, and P.S. Vassilevski, Domain decomposition type iterative techniques for parabolic problems on locally refined grids, SIAM J. Numer. Anal., v. 30, 1993, N 6, 1537-1557, MR# 95i:65094
101. G. Carey, R.D. Lazarov, and A. Pehlivanov, Least-squares mixed finite elements for second order elliptic problems, SIAM J. Numer. Anal., v 31 (5) (1994), 1368-1377. MR#95i:65206
102. Z. Cai, R.D. Lazarov, T.A. Manteuffel, and S.F. McCormick, First order systems least-squares for partial differential equations: I Discretization, SIAM J. Numer. Anal., v. 31 (6) (1994), 1785-1799. MR# 95f:65133
103. R.E. Ewing and R.D. Lazarov, Approximation of parabolic problems on grids locally refined in time and space, Appl. Numerical Mathematics, v. 14 (1994), 199-211
104. R. Ewing, R. Lazarov, Yu. Kuznetsov, and S. Maliassov, Preconditioning of nonconforming finite element systems of second order elliptic problems, Advances in Numer. Meth. Appl., Sofia, 1994, Proc. Third Int. Conference (I. Dimov et al. Eds.), World Scientific, 101-110.
105. H. Chen, R. Ewing, and R.D. Lazarov, Superconvergence of the mixed finite element approximations to parabolic equations, Advances in Numer. Meth. Appl., Sofia, 1994, Proc. Third Int. Conference (I. Dimov et al. Eds.), World Scientific, 63-70.
106. R.D. Lazarov, I.D. Mishev, and P.S. Vassilevski, Finite volume methods for convection-diffusion problems, SIAM J. Numer. Anal., v. 33 (1) (1996), 31 - 55 (also as Technical Report ISC-94-03-MATH, Texas A& M University )
107. R.Ewing, R.D. Lazarov, and A. Vassilev, Finite difference schemes for parabolic problems on composite grids with refinement in time and space, SIAM J. Numer. Anal., v. 31 (6) (1994), 1605-1622. MR# 95j:65095
108. R. Ewing, R. Lazarov, Yu. Kuznetsov, and S. Maliassov, Substructuring preconditioning for finite element approximations of second order elliptic problems, Finite Element Modeling of Environmental Problems. Surface and Subsurface Flow and Transport, G.F. Carey, Eds., J. Wiley, 1995, 303-331.
109. P.S. Vassilevski, S. Petrova, and R.D. Lazarov, Preconditioning elliptic problems on grids with multilevel local refinemnet, Methematica Balkanica, v. 8 (2-3) (1994), 179 - 196.
110. R.D. Lazarov, I.D. Mishev, and P.S. Vassilevski, Finite volume approximation of convection-diffusion problems on grids with local refinement, Computing, v. 53 (1) 1994, 33-57. MR# 95f:65196
111. J.H. Bramble, R.D. Lazarov, and J.E. Pasciak, A least-squares approach based on a discrete minus one inner product for first order systems, Technical Report 94-32 of Mathematical Science Institute, Cornell University, Math. Comp., 66 (1997), 935 - 955.
112. Z. Chen, R. Ewing, and R. Lazarov, Domain decomposition algorithms for mixed methods for second order elliptic problems, Math. Comp., v. 65 (1996), 467 - 490.
113. R. Ewing, R. Lazarov, Yu. Kuznetsov, and S. Maliassov, Preconditioning for nonconforming finite element approximations of second order elliptic problems, (also as Technical Report ISC-94-02-MATH, Texas A& M University )
114. R.D. Lazarov and P.S. Vassilevski, Preconditioning saddle-point problems arising from mixed finite element discretizations of elliptic equations, Numer. Lin. Algebra Appl., v. 3(1) (1996), 1 - 20.
115. Z. Chen, R. Ewing, R. Lazarov, Yu. Kuznetsov, and S. Maliassov, Multilevel preconditioners for mixed methods for second order elliptic problems, Numer. Lin. Alg. Appl., 3 (1996), 427 - 453. (also as Technical Report ISC-94-14-MATH, Texas A& M University )
116. H.S. Chen, R.E.Ewing, and R.D. Lazarov, Superconvergence of the mixed finite element methods for parabolic problems with nonsmooth initial data, Numer. Mathematik, v. 78 (1998), 495-521 (also as Technical Report ISC-94-04-MATH, Texas A& M University )
117. R.E.Ewing and R.D. Lazarov, Computational Techniques in Multiphase Flow and Transport in Porous Media, Proc. Int. Conference on Mathematics and Computations, Reactor Physics, and Environmental Analysis, Portland, Oregon, April 30 - May 4, 1995, 414-420, American Nuclear Society Inc., 1995.
118. R.E. Ewing, R.D. Lazarov, J.E. Pasciak, and A. Vassilev, Mathematical modeling, Numerical Techniques, and Computer Simulation of flows and transport in porous media, Proc. Comput. Techniques and Applications: CTAC95, World Scientific, Singapore, 1996, 13-30.
119. H.S. Chen and R.D. Lazarov, Error analysis of fully discrete mixed finite element approximations to parabolic problems, Technical Report ISC-95-06-MATH, Institute for Scientific Computation, Texas A&M University, 1995.
120. H.S. Chen and R.D. Lazarov, Domain splitting algorithm for mixed finite element approximations to parabolic problems, East-West J. Numerical Mathematics, v. 4 (1996), 121-135, (also as Technical Report ISC-95-07-MATH, Texas A& M University )
121. R.D. Lazarov and I.D. Mishev, Finite volume method for reaction-diffusion problems, Proc. First Intern. Symposium on Finite Volume Methods for Complex Applications (F. Benkhaldoun and R. Vilsmeier, Eds.), July 15 - 18, 1996, Rouen, France, pp. 233 - 240
122. J. Bramble, R. Lazarov, and J. Pasciak, Least-squares for second order elliptic problems, Comput. Meth. Appl. Mech. Engn., v. 152 (1998), Nos.1-2, pp. 195-210.
123. R.D. Lazarov, L. Tobiska, and P. Vassilevski, Stream-line diffusion least-squares mixed finite element methods for convection-diffusion problems, East-West J. Numerical Mathematics, v. 5 (1997), No.4, pp. 321-335.
124. B. Jovanovic, R. Lazarov, and I. Sestak, A note on the least-squares finite elements for elliptic problems in mixed form, Technical Report ISC-98-08-MATH, Texas A& M University
125. R.E. Ewing, R.D. Lazarov, S.L. Lyons, D. Papavassiliou, and J.E, Pasciak, Numerical Well Model fof Non-Darcy Flow, Computational Geosciences, v.3 (1999), 185--204.
126. R.E. Ewing, R.D. Lazarov, and Y. Lin, Finite volume element approximations of non-local in time one-dimensional reactive flows in porous media, Technical Report ISC-98-06-MATH, Texas A& M University, Computing, v. 64 (2000) pp. 157--182.
127. R.E. Ewing, R.D. Lazarov, and Y. Lin, Finite volume element approximations of non-local reactive flows in porous media, Technical Report ISC-98-08-MATH, Texas A& M University, Numerical Methods for PDEs, v. 16 (2000), pp. 285--311.
128. R.D. Lazarov and P.S. Vassilevski, Least-squares streamline diffusion finite element approximations to singularly perturbed convection-diffusion problems, TR ISC-99-02-MATH, Texas A& M University, Analytical and Numerical Methods for Singularly Perturbed Problems, L.G. Vulkov, J.J.H. Miller, and G.I. Shishkin, Eds, Nova Science Publishing House, 2000, pp. 71--82.
129. R.D. Lazarov, J.E. Pasciak and S.Z. Tomov, Error control, local grid refinement, and efficient solution algorithms for singularly perturbed problems, TR ISC-99-04-MATH, Texas A& M University, Analytical and Numerical Methods for Singularly Perturbed Problems, L.G. Vulkov, J.J.H. Miller, and G.I. Shishkin, Eds, Nova Science Publishing House, 2000, pp. 83--54
130. R. Ewing, R.Lazarov, and Y. Lin, Finite volume element approximations of integro-differential parabolic problems, Recent Adavances in Numerical Methods and Applications (O. Iliev, M. Kaschiev, S. Margenov, Bl. Sendov, P. Vassilevski, Eds.), Proc. Fourth Int. Conf., NMA'98, Sofia, 1998, World Scientific, 1999, pp. 3--15.
131. R. Ewing, R. Lazarov, T. Lin, and Y. Lin, Domain decomposition capabilities for the mortar finite volume element methods, Technical Report ISC-98-12-MATH, Texas A&M University, 11-th International Conference on Domain Decomposition Methods in Science and Engineering, London, 1998, C.H. Lai, P.E. Bjorstad, M. Cross, and O.Widlund, Eds, DD Press, Bergen, 1999, pp. 220--227.
132. R.D. Lazarov, J.E. Pasciak, and P.S. Vassilevski, Coupling mixed and finite volume discretizations of convection-diffusion-reaction equations on non-matching grids, Technical Report ISC-99-07-MATH, Texas A& M University, Finite Volumes for Complex Applications II. Problems and Perspectives, R. Vilsmeier, F. Benkhaldoun, and D. Hanel eds, Hermes Science Publications, Paris, 1999, pp. 51--68.
133. R.D. Lazarov, J.E. Pasciak and P.S. Vassilevski, Iterative solution of a conbined mixed and standard Galerkin discretization method for elliptic problems, Technical Report, ISC-99-03-MATH, Texas A& M University Numer. Linear Algebra Appl., 8 (2001), 13-31.
134. R.E. Ewing, O.P. Iliev, and R.D. Lazarov, A modified finite volume approximation of second-order elliptic equations with discontinuous coefficients, Technical Report, ISC-99-01-MATH, Texas A& M University SIAM Sci. Comput., 23 (4) (2001), 1334--1350.
135. R.D. Lazarov J.E. Pasciak and P.S. Vassilevski, Mixed finite element methods for elliptic problems on non-matching grids, Large Scale Scientific Computations of Engineering and Environmental Problems II, (M. Griebel, S. Margenov and P. Yalamov, Eds) Notes in Numerical Fluid Mechanics, v. 72 (2000), 25--35.
136. J. Bramble, R. Lazarov, and J. Pasciak, Least-squares methods for linear elasticity based on a discrete minus one inner product, Technical Report ISC-99-05-MATH, Texas A&M University , Computer Meth. Appl. Mech. Engrg., 191 (2001) 727--744
137. R. Ewing, R. Lazarov, T. Lin, and Y. Lin, Mortar finite volume element approximations of second order elliptic problems, Technical Report ISC-99-08-MATH, Texas A&M University , East-West J. Numer. Math., v. 8 (2000), 168-183.
138. R.D. Lazarov and S.Z. Tomov, Adaptive finite volume element method for convection-diffusion-reaction problems in 3-D, Technical Report ISC-00-02-MATH, Texas A& M University, Advances in Computation: Theory and Practice, Vol. 7, Scientific Computing and Applications (P. Minev and Y. Lin, Eds), Nova Sci. Publishers, Inc., (2001), 91-106.
139. T. Chernogorova, R.E. Ewing, O.P. Iliev, and R.D.Lazarov, On the discretization of interface problem with perfect and imperfect contacts, Technical Report ISC-00-03-MATH, Texas A&M University , Proc. Int. Conf. on Numerical Treatment of Multiphase Flows in Porous Media, Z. Chen, R. Ewing, and Z. Shi, Eds, Lecture Notes in Physics, v. 552 (2000), 93--103.
140. R. Ewing, A. Ibragimov, and R.Lazarov, 3-D simulation of the pressure drop along horizontal wells in a bounded reservoir, SPE#65505, presented at SPE Int. Conference on Horizontal Well Technology, Calgary, Canada, Nov. 6-8, 2000.
141. C. Kim, R.D. Lazarov, J.E. Pasciak, and P.S. Vassilevski, Multiplier spaces for the mortar finite element method in three dimensions, SAM Numer. Anal., 39 (2) (2001), 519-538 (also as Technical Report ISC-00-05-MATH, Texas A& M University).
142. R.D. Lazarov, S.Z. Tomov, and P.S. Vassilevski, Interior penalty discontinuous approximations of elliptic problems, Technical Report ISC-00-04-MATH, Texas A& M University, Comput. Methods Appl. Math., 1 (4) (2001), 367-382
143. R.E. Ewing, A. Ibragimov, and R.D. Lazarov, Domain decomposition algorithm and analytical simulation of coupled flow in reservoir/well system, J. Korea SIAM , 5 (2) (2001), 71-99.
144. R.D. Lazarov, Bramble-Hilbert Lemma, Encyclopaedia of Mathematics. Supplement III, Kluwer Academic Publishers (2001), 79-81.
145. R.D. Lazarov and S.Z. Tomov, A posteriori error estimates for finite volume element approximations of convection-diffusion-reaction equations, Technical Report ISC-00-02-MATH, Texas A& M University, Comput. Geosciences, 6 (3-4) (2002) 483 - 503.
146. R.D. Lazarov and P.S. Vassilevski, Numerical methods for convection-diffusion problems on general grids , Approximation Theory, A volume dedicated to Blagovest Sendov, B. Bojanov(Ed.), Darba, Sofia, 2002, 258 - 283.
147. P. Chatzipantelidis and R.D. Lazarov, The finite volume element method in nonconvex domains, Finite Volumes for Complex Applications III, R. Herbin and D. Kroner, Eds, Hermes Penton Science, 2002, 171 - 178.
148. T.I. Chernogorova, R.E. Ewing, O.P. Iliev, and R.D. Lazarov, On finite volume discretzation of elliptic interface problem, Finite Volumes for Complex Applications III, R. Herbin and D. Kroner, Eds, Hermes Penton Science, 2002, 301 - 308.
149. R.D. Lazarov, J.E. Pasciak, J. Schoberl, and P.S. Vassilevski, Almost optimal interior penalty discontinuous approximation of symmetric elliptic problems on non-matching grids, Numerische Mathematik, 96 (2) , (2003) 295--315.
150. R.D. Lazarov and S. Margenov, On a two-level parallel MIC(0) preconditioning of Crouzeix-Raviart non-conforming FEM systems , Springer Lecture Notes in Computer Science , 2542, (2003) 192--204 (also as Technical Report ISC-02-06-MATH , Texas A& M University)
151. Douglas C.C.,Efendiev Y., Ewing R., Lazarov R., Cole M.J., Jones G., Johnson C.R., Virtual telemetry for dynamic data-driven application simulations, Springer Lect. Notes in Comp. Sci., 2660 , (2003) 279 - 288.
152. C. Carstensen, R.D. Lazarov, and S. Tomov, Explicit and averaging a posteriori error estimates for adaptive finite volume methods, SIAM J. Numer.Anal. 42 (6) (2005) 2496 -- 2521 (also as Isaac Newton Institute for Mathematical Sciences, (2003), Cambridge University, UK)
153. P. Chatzipantelidis, R.D. Lazarov, and V.Thomee, Error estimates for the finite volume element method for parabolic equations in convex polygonal domains, Technical Report ISC-03-03-MATH , Texas A& M University Numer. Meth. PDEs, 20 (5) , (2004) 650 -- 674.
154. V. Ginting, R. Ewing, Y. Efendiev, and R. Lazarov, Upscale modeling for multiphase flow, J. Comput. Appl. Math., 24 , n. 2, (2004).
155. P. Chatzipantelidis and R.D. Lazarov, Error estimates for finite volume element method for elliptic PDE's in nonconvex polygonal domains, SIAM J. Numer.Anal. 42 (5) (2005) 1932 -- 1958 (also, Technical Report ISC-03-03-MATH , Texas A& M University.
156. P. Chatzipantelidis, V. Ginting, and R.D. Lazarov, A finite volume element method for nonlinear elliptic problems, Technical Report ISC-04-05-MATH , Texas A& M University Numer. Linear Algebra Appl. 12 (2005) 515-545
157. A.B. Andreev, R.D. Lazarov, and M.R. Racheva, Postprocessing and Higher Order Convergence of Mixed Finite Element Approximations of Biharmonic Eigenvalue Problems, Technical Report ISC-04-04-MATH , Texas A& M University J. Comput. Appl. Math., 182 (2) (2005) 333-349
158. C.C. Douglas, Y. Efendiev, R.E. Ewing, V. Ginting, R.D. Lazarov, M.J. Cole, G. Jones, Least-squares approach for data recovery in dynamic data-driven applications simulations, to appear in Journal of Computing and Visualization in Science , submitted November (2004)
159. C.C. Douglas, Y. Efendiev, R.E. Ewing, V. Ginting, R.D. Lazarov, M.J. Cole, G. Jones, and C.R. Johnson, Multiscale Interpolation, Backward in Time Error Analysis for Data-Driven Contaminant Simulation, In ICCS 2005: Proc. 5th International Conference, Part II, V.S. Sunderam et al.(Eds), Lecture Notes in Computer Science , 3515, (2005), 640-647
160. R.D. Lazarov, and L.T. Zikatanov, An exponential fitting scheme for general convection-diffusion equations on tetrahedral meshes, Technical Report ISC-04-15-MATH , Texas A& M University, J. Comput. Math. (Obchysljuval'na ta prykladna matematyka, Kiev), 1 (92) (2005) 60-69.
161. P. Chatzipantelidis and R.D. Lazarov, Error estimates for a finite volume element method for elliptic PDE's in nonconvex polygonal domains , SIAM J. Numer. Anal. 42 (5) (2005) 1932 -- 1958
162. A.B. Andreev, R.D. Lazarov, and M.R. Racheva, Postprocessing and Higher Order Convergence of Mixed Finite Element Approximations of Biharmonic Eigenvalue Problems, Technical Report ISC-04-04-MATH , Texas A& M University, J. Comput. Appl. Math., 182 (2) (2005), 333--349.
163. C. Carstensen, R.D. Lazarov, and S.Z. Tomov, Explicit and averaging a posteriori error estimates for adaptive finite volume methods , SIAM J. Numer. Anal. 42 (6) (2005) 2496 -- 2521.
164. P. Chatzipantelidis, V. Ginting, and R.D. Lazarov, A finite volume element method for nonlinear elliptic problems Technical Report ISC-04-06-MATH , Texas A& M University, Numer. Linear Algebra Appl. , 12 (2005) 515--546.
165. P. Chatzipantelidis and R.D. Lazarov, Error estimates for a finite volume element method for elliptic PDE's in nonconvex polygonal domains , SIAM J. Numer. Anal. 42 (6) (2005), 1932--1958.
166. C. Duoglas, Y. Efendiev, R. Ewing, V. Ginting, and R. Lazarov, Dynamic data driven simulations in stochastic environments, Computing, 77 (4), 2006, 321--333
167. P. Chatzipantelidis, R.D. Lazarov, V. Thomee, and L.B. Wahlbin, Parabolic finite element method equations in nonconvex polygonal domains, BIT Numerical Mathematics 46 (Suppl. 1) 2006, S113--S143
168. Douglas, C.C., Clay Harris, J., Iskandarani, M., Johnson, C.R., Lodder, R.J., Parker, S.G., Cole, M.J., Ewing, R., Efendiev, Y., Lazarov, R., Qin, G., Dynamic contaminant identification in water, Lecture Notes in Computer Science (LNCS) 3993 , 2006, 393--400
169. V.A. Dobrev, R.D. Lazarov, P.S. Vassilevski, and L.T. Zikatanov, Two-level preconditioning of discontinuous Galerkin approximations of second order elliptic equations Numer. Lin. Alg. Appl., 13 (9) 2006, 753--770
170. R.K. Sinha, R.E. Ewing, and R.D. Lazarov, Some new error estimates of a semidiscrete finite volume element method for parabolic integro-differential equation with nonsmooth initial data, Technical Report ISC-04-16-MATH , Texas A& M University, SIAM J. Numer. Anal. 43 (6) (2006) 2320--2344.
171. R.E. Ewing, O.P. Iliev, R.D. Lazarov, and A. Naumovich, On convergence of certain finite volume difference discretizations for 1-D poroelasticity interface problems, Published Online: 16 Nov 2006 in Numer. Methods for Partial Differential Equations, 23 (3) (2007), 652-671.
172. R.D. Lazarov and X. Ye, Stabilized discontinuous finite element approximations for Stokes equations, J. Comput. Appl. Math., 198 (1) (2007), 236--252.
173. R.D. Lazarov and S.D. Margenov, CBS constants for graph-Laplacians and application to multilevel methods for discontinuous Galerkin systems, J. Complexity 23 (4-6) (2007), 498 -- 515.
174. R. Lazarov, S. Lu, S. Pereverziev, On the balancing principle for some problems of numerical analysis, Numer. Math. 106 (4) (2007), 659--689.
175. R.Ewing, R. Lazarov, V.Makarov, and T. Vashakmadze, New mathematical models for thin-walled solid structures and projective methods for their solution, AMIM, vol. 12, (2) (2007), 82--108.
176. V.A. Dobrev, R.D. Lazarov, and L.T. Zikatanov, Preconditioning of symmetric interior penalty discontinuous Galerkin FEM for second order elliptic problems , In Domain Decomposition Methods Science and Enginering XVII, Lecture Notes in Computational Science and Engineering, vol. 60, U. Langer et al. eds, Springer-Verlag, Berlin, Heidelberg, pp. 33--44 (2008).
177. B. Cockburn, J. Gopalakrishnan, and R. Lazarov, Unified hybridization of discontinuous Galerkin, mixed, and conforming methods for second-order elliptic problems SIAM J. Numer. Anal. , 47 (2) (2009), 1319--1365.
178. R. Lazarov, S. Repin, and S. Tomar, Functional a posteriori error estimates for discontinuous Galerkin approximations of elliptic problems, J. Numerical Methods for PDEs, 25 (4) (2009), 952--971.
179. P. Chatzipantelidis, R. Lazarov, and V. Tomee, Parabolic finite volume element equations in nonconvex polygonal domains, ISC Technical Reports, ISC-07-08-MATH, Institute for Scientific Computation, J. Numerical Methods for PDEs, 25 (3) (2009), 520--537.
180. R.E. Ewing, O.P. Iliev, R.D. Lazarov, I. Rybak, and J. Willems, A simplified method for upscaling composite materials with high contrast of the conductivity, SIAM J. Scientific Computing, 31 (4) (2009), 2568--2586.
181. O.P. Iliev, R.D. Lazarov, and J. Willems, Fast Numerical Upscaling of Heat Equation for Fibrous Materials, submitted to J. Computing and Visualization in Science, April 2009

Books and Special Volumes:

1. A. Andreev, B. Boyanov, S. Dimova, R. Lazarov, and M.Nikolcheva, Collection of Problems on Numerical Analysis, Nauka i Izkustvo Publ. House, Sofia, 1985 (Bulgarian)
2. A. Andreev, M. Apostolova, P. Binev, B. Boyanov, T. Boyanov, S. Dimova, D. Dryanov, A. Yotova, G. Nikolov, R. Lazarov, M.Nikolcheva, M. Petkov, and T. Chernogorova, Collection of Problems on Numerical Analysis, Sofia University Publ. House, Sofia, 1994 (Bulgarian)
3. A.Samarskii, R. Lazarov, and and V. Makarov, Difference Schemes for Differential Equations Having Generalized Solutions, Visshaya Shkola Publ., Moscow, 1987, 296 pp.
4. V.M. Petkov and R.D. Lazarov (Editors), Pitman Research Notes in Mathematics Series 235, Integral Equatioins and Inverse Problems, Longman Scientific & Technical, 1990, 285 p.

Other Publications, Technical Reports, Programming Products:

1. Evaluation of parameters of exterior illumination appliances by means of computers, Comm. VMEI, Sofia, v.24(6) (1969), 135-148 (with N.Vassilev and D.Royalski, Bulgarian)
2. Finite difference schemes for elasticity problems in curvelinear domains, Autoreferat of Ph.D. Thesis (candidate of sciences), Moscow State University, Moscow, 1972 (Russian)
3. Scientific subroutine package for numerical treatment of differential equations, Program N 1.2310.0010-01, 1974
4. On a numerical solution of a quasilinear problem of heat transfer, Proc. National School on Application of Computers in Engineering, Primorsko, 1975, 161-167 (with N.Vulchanov and A. Hatchikian, Bulgarian)
5. Some methods of discretization of problems of mathematical physics, Proc. National School on Application of Computers in Engineering, Primorsko, 1975, 195-208 Bulgarian)
6. Computing of thermal fields in welding of 2-D bodies, Dept. Material Sci., VMEI, Sofia, 1975, 135-140 (with M.Mikhailov and G.Saev, Bulgarian)
7. Scientific subroutine package for problems in science and engineering, Part 3, Program N 1.2310.00531-01, 1976
8. Problems with free lines, Proc. National School of Young Scientists, VMEI, Sofia, 1976 (with V.Liubenov et all., Bulgarian), 62-67
9. Numerical methods for the problems of physics, mechanics and technique using computers, Rutherford Laboratory, Didcot, UK, Final Report, 1977
10. Mathematical models of steel crystalization of cylindrical block of nitrogen steel without nickel, Second Sci. Conference on Steel Casting Production, Varna, October 4-6, 1979 (with I.Dimov et al., Russian)
11. Mathematical model of steel crystalization in the upper part of the mould, Second Sci.Conference on Steel Casting Production, Varna, October 4-6, 1979 (with I.Dimov et al., Russian)
12. Numerical methods, algorithms and programs for solving heat equation, describing crystalization processes in steel casting, Internal Report on Contract No 77-440-0093, 1979.
13. Error estimates of the difference schemes for some problems of mathematical physics having generalized solutions, Autoreferat of Diss. Dr. Sci., Sofia University, Sofia, 1981 (Bulgarian)
14. Computing thermal fields in ingot steel casting, Technical Report on Contract No 80-440-0144, 1981
15. Scientific subroutine package for solving thermal problems, Program N 1.2310.00864-01, 1983
16. Influence of some constructive factors on the parameters of piesoresistive pressure sensors, Fifth International Conf. on Microelectronics'86, Plovdiv, October 23-25,1986 (with P. Peykov, Bulgarian)
17. Investigation of crystalization processes in heat transfer in ingot casting, Technical Report for Contract No 83-440-0195, 1986
18. New generation high performance computer systems, Current Problems in Sciences, Bulg. Acad. Sci., 13, 1986, 1-76 (with K. Boyanov et al., Bulgarian)
19. Investigation of the heat transfer during flow of liquid steel in feeding systems of matalugical mashines, Ann. Higher of Chemical Engineering, Sofia, v. 29, 1989, N 4.
20. Pointwise local refinement and BEPS-preconditioning for elliptic problems on cell-centered grids (with S. Margenov), EORI University of Wyoming, Preprint #1992-09, 12 p.
21. Numerical simulation of transport contamination due to flow in liquid and porous media (with R.E.Ewing and O.P.Iliev), EORI, University of Wyoming, Preprint #1992-10, 26 pp.

Invited Talks:

1. Difference schemes of second order accuracy for some axially symmetric elastic problems, 7 Tagung uber Probleme and Methoden der Mathematische Physik, Karl-Marx-Stadt TH, June 13-22, 1979.
2. Mathematical modeling in casting processes, Inst.S. Banach, Semester on Computational Mathematics, Warsaw, March 31-April 9, 1980.
3. Numerical treatment of some problems of the flow and instability of liquid jets, Mathemat. Methoden der Stromugsmechanik, Oberwolfach, November 29-December 5, 1981.
4. Error analysis of the finite element solutions to differential equations, 13 th Summer School on Application of Mathematics in Technique, Varna, September 1-8, 1982.
5. On the convergence of finite difference schemes for Poisson's equation in discrete H^1-norms, Tage der Wissenschaft und Technik Ing.Hohschule, Wismar, Germany, October 15-17, 1982.
6. On the convergence of the difference scheme for the second boundary value problem for the biharmonic equation with solution from Wpk, Seminar on Mathematical Models in Physics, and Chemistry and Numerical Methods of Their Realization, Visegrad, Hungary, September 27-October 10, 1982.
7. Superconvergence of the gradient in FEM for some elliptic and parabolic problems, 5th All Union Convergence on Variational-Difference Methods in the Mathematical Physics, Moscow, 24-26 May, 1983.
8. Error estimates of some finite difference schemes for differential equations having generalized solutions, 8 TMP, Karl-Marx-Stadt TH, June 20-24, 1983.
9. Difference schemes for elliptic problems with generalized solutions, Multigrid Methods, Oberwolfach, December 9-15, 1984.
10. Superconvergence of the gradient for triangular finite elements, EQUADIFF, 6th Czechoslovak Conference on Differential Equations and Their Applications, Brno, August 26-30, 1985.
11. Superconvergence of the gradient for triangular and tetrahedral finite elements for linear elastic problems, Conference on Modern Problems of Numerical Analysis, Academy of Science of USSR, Moscow, September 14-18, 1986.
12. Convergence of the finite difference schemes for problems with generalized solutions, Conference on Numerical and Analytical Methods for Differential and Integral Equations, Academy of Science of DDR, Frankfurt am Oder, October 1-4, 1986.
13. Study of some physical process via numerical experiment, First National School on Application of Computers in the Research, Varna, November 10-15, 1986.
14. Superconvergence in the finite element method, Semester on Numerical Analysis and Mathematical Modeling, Inst. S. Banach, Warsaw, March 20-25, 1987.
15. Boundary element method for problems of ideal fluid flow with free surfaces, 9th Int. Conference on BEM in Engineering, University of Stuttgart, September 1-4, 1987.
16. Adaptive local grid refinement, Rocky Mountain Regional Meeting of SPE, Casper, May 11-13, 1988.
17. Local refinement techniques in the finite element and finite difference methods, Int. Conference on Numerical Methods and Appl., Sofia, August 22-27, 1988.
18. Iteration methods for numerical solution of differential equations on grids with local refinement, Int. Conf. on Diff. Equations and Applications, Russe, August 13-17, 1989.
19. Local superconvergence analysis of the approximate boundary flux calculations, Int. Conf. EQUADIFF'7, Prague, August 21-24, 1989.
20. On some efficient numerical methods for solving Poisson equation. Int. conf. on Differential Equations and Inverse Problems, Varna, September 18-23, 1989.
21. Local refinement techniques for fluid flow in porous media, Sixth National Congress on Mechanics, Varna, September 25-30,1989
22. Mathematical modelling of some heat transfer processes in the steel casting industry, Int. Conf. on High Nirtogen Steels,Varna, October 1-3,1989
23. Finite difference schemes on grids with local refinement in time and in space for parabolic problems. Optimal two-grid iterative methods, Sixth GAMM-Seminar on Parallel Algorithms for PDE's, Kiel, January 17-21, 1990
24. Mixed finite element solution of second order elliptic problems on grids with regular local refinement, Fourth Int.Conf. on Domain Decomposition, Moscow, May 20-25, 1990
25. An implicit finite difference scheme for solving parabolic problems on composite grids with refinement in space and in time, International Seminar on Computational Mathematics, Academy of Sciences of USSR, Moscow, June 17-19, 1991
26. Local Refinement Technique via Domain Decomposition for Parabolic Problems, International Conference on Domain Decomposition, Lambrecht, Germany,September 2-7, 1991
27. Finite elements in computer simulation of underground flow and transport, Workshop on Finite Element Modeling in Environmental Problems, March 4-5, 1994, University of Texas at Austin, Austin.
28. Accuracy of the finite element methods for least-squares functionals, Workshop on First-Order Systems Least-Square Functionals, Los Alamos National Laboratory, May 25-27, 1994.
29. Least-squares method for first order systems obtained from splitting second order elliptic equations, Fifth International Colloquium on Differential Equations, Plovdiv, Bulgaria, August 18-22, 1994.
30. Superconvergence of the mixed finite element methods for parabolic problems with nonsmooth initial data, Conference on Numerical methods and Applications, Sofia, Bulgaria, August 22 - 27, 1994.
31. H^1-error estimates for the finite volume approximations of convection-diffusion problems, International Conference on Finite Volume Methods, Oberwolfach, Germany, Oct. 30 - Nov. 4, 1994.
32. Domain Decomposition Methods for Mixed Finite Element Approximations to Flow Problems, SIAM Conference on Geosciences, San Antonio, Feb. 8-11, 1995
33. Computational Techniques in Multiphase Flow and Transport in Porous Media, Proc. International Conference on Mathematics and Computations, Reactor Physics, and Environmental Analysis, Portland, Oregon, April 30 - May 4, 1995, 414-420.
34. Domain Splitting Algorithms for Mixed Finite Element Approximations to Convectio-Diffusion Problems, Third U.S. National Congress on Computational Mechanics, Dallas, June 12-14, 1995.
35. Mathematical Modeling, Numerical Techniques, and Computer Simulation of Flow and Transport in Porous Media, Computational Techniques and Applications Conference, Melbourne, Australia, July 3 - 7, 1995.
36. Domain splitting algorithm for mixed finite element approximations to parabolic problems, Workshop on Iterative Methods for Large Scale Nonlinear Problems, Logan, Utah, September 14-16, 1995.
37. Least-squares finite element methods for second order elliptic problems, Conference on Analysis, Numerics and Applications of Differential and Integral Equations, Stuttgart, Germany, October 9 - 11, 1996.
38. Finite volume and finite volume element methods for convection-diffusion problems, Fourth SIAM Conference on Mathematical and Computational Issues in the Geosciences, June 16-18, 1997, Albuquerque, New Mexico.
39. Stream-line diffusion mixed least-squares method for ingularly perturbed convection-diffusion problems, Conference on Numerical Methods for Singular Perturbations, April 12-18, 1998, Oberwolfach, Germany.
40. Finite volume methods for time dependent problems and their analysis, Conference on Finite Difference Methods, July 6 - 9, 1998, Minsk, Belorussia.
41. Finite volume methods for steady-state and transient problems, 4-th Interenational Conference on Numerical Methods and Applications, August 19-23, 1998, Sofia, Bulgaria.
42. Error control, local grid refinement, and efficient solution strategies in numerical methods for singularly perturbed problems, Workshop on Singularly Perturbed Problems, August 26-31, 1998, Lozenetz, Bulgaria.
43. Combining the mixed finite element and the finite volume methods, Fifth SIAM Conference on Mathematical and Computational Issues in the Geosciences, March 24-27, 1999, San Antonio, Texas.
44. Coupling various methods for convection-diffusion problems with Applications to flows in porous media, Second Int. Workshop on Large Scale Scientific Computing, June 2-6, 1999, Sozopol, Bulgaria.
45. Finite volume approximations ans mortar domain decomposition methods on nonmatching grids, Second Int. Symposium on Finite Volumes for Complex Applications, July 19-22, 1999, Duisburg, Germany.
46. Locally conservative discretizations on non-matching grids, 948th AMS Meeting, October 8-10, 1999, University of Texas, Austin, Texas.
47. Locally conservative discretizations on non-matching grids with application to ground-water flows, Workshop on Confinment and Remediation of Environmental Hazards, January 15 - 20, 2000, IMA, University of Minnesota (part of the 1999-2000 program on Reactive Flows and Transport Phenomena).
48. Adaptive finite volume element method for convection-diffusion-reaction problems in 3-D, Workshop on Large Scale Scientific Computing, May 28 - June 2, 2000, Kananaskis, Canada.
49. Discretizations on non-matching grids and domain decomposition, Second Conference on Numerical Analysis and Applications, June 11 -- 15, 2000, Rousse, Bulgaria.
50. Tool-box for parallel simulation of flows in porous media, Cross Discipline Ecosystem Modeling and Analysis Workshop, August 15-17, 2000, U.S. EPA, Research Triangle Park, NC.
51. Adaptive methods for 3-D elliptic and parabolic equations with applications to flows in porous media, International Congress on Computational Methods for Porous Media, May 13 - 15, 2001, Fes, Morocco.
52. Adaptive multilevel methods for convection-diffusion-reaction equations, Preconditioned Robust Iterative Solution Methods for Problems with Singularities (PRISM2001), May 21 - 23, 2001, University of Nijmegen, Netherlands.
53. Finite volume methods for convection-diffusion-reaction equations with applications to flows in porous media, AMS-IMS-SIAM Summer Research Conferences: Fluid Flow and Transport in Porous Media: Mathematical and Numerical Treatment, June 17 - 22, 2001, Mount Holyoke College, South Hadley, Massachusetts.
54. Adaptive inite volume methods for elliptic problems, Conference in Numerical Analysis, June 5-9, 2002, Krynica, Poland.
55. The finite volume element method in nonconvex domains, Third Int. Symposium on Finite Volumes for Complex Applications, June 24 - 28, 2002, Porquerolles, France.
56. Error control and adaptive meshes in finite volume methods for elliptic problems, Fifth International Congress on Numerical Methods and Applications, August 21 - 24, 2002, Borovetz, Bulgaria.
57. Error analysis and error control for finite volume methods for convection-diffusion problems, International Workshop on Numerical and Symbolic Scientific Computing, June 16-21, 2003, Stroble, Austria.
58. Finte volume methods: error analysis, error control and solution techniques, Fourth International Conference on Large Scale scientific computations, June 3-9, 2003, Sozopol, Bulgaria.
59. Error control in finite volume approximations of conevection-diffusion-reaction problems, Seventh US Congress on Computational Mechanics, Albuquerque, July 27 - 31, 2003.
60. Discontinuous Galerkin method for first order euqations, Workshop on Numerical Methods for PDEs, June 10, 2004, University of Kaiserslautern, Germany.
61. Discontinuous Galerkin method for second order euqations as stabilization of mixed formulation, Workshop on Numerical Methods for PDEs, June 10, 2004, University of Kaiserslautern, Germany.
62. A finite volume method for nonlinear elliptic problems, IMA "Hot Topics" Workshop on Comaptible Spatial Discretizations for PDEs, May 11 - 15, 2004, University of Minnesota, Minneapolis
63. Mathematical modeling and approximation methods for susrface and subsurface water flows, Workshop on Mathematical Modeling and Numerical Analysis, March 15, 2004, Tbilisi, Georgia.
64. Error analysis and error control of FEM for convection-diffusion problems, 5th Annual Conference of the Los Alamos Computer Science Institute, October 12 - October 15, 2004, Santa Fe, New Mexico.
65. Finte volume approximation of convection-diffusion problems: error analysis and error control, Third International Conference on Numerical Analysis and Applications, June 29 - July 3, 2004, Rousse, Bulgaria.
66. Discretization of elliptic interface problems with perfect and imperfect contact, Third International Conference on Numerical Analysis and Applications, June 29 - July 3, 2004, Rousse, Bulgaria.
67. Finte volume approximation of convection-diffusion equations, International Conference on Modern Numerical Method, June 14-19, 2004, Bedlewo, Banach Mathematical Center, Poland.
68. Finite volume approximation of convection-diffusion problems: error analysis and error control, Third International Conference on Numerical Analysis and Applications, June 29 - July 3, 2004, Rousse, Bulgaria.
69. Error analysis and error control of FEM for convection-diffusion problems, 5th Annual Conference of the Los Alamos Computer Science Institute, October 12 - October 15, 2004, Santa Fe, New Mexico.
70. Discontinuous Galerkin method as a stabilization technique for nonconforming finite element approiximations of PDEs, Fourth International Conference on Large Scale Scientific Computations, June 3-9, 2005, Sozopol, Bulgaria.
71. Discontinuous Galerkin methods, Kick-off Meeting of RICAM Special Semester on Computationla Mechanics, October 3 - October 4, 2005, Linz, Austria.
72. On the balancing principle for the choice of weight in penalization methods, Miniworkshop on Domain Decomposition Methods, RICAM Special Semester on Computationla Mechanics, November 18, 2005, Linz, Austria.
73. Preconditioning DG systems, Miniworkshop on Discontinuous Galerkin Methods, RICAM Special Semester on Computationla Mechanics, November 29, 2005, Linz, Austria.
74. Hybridization of interior penalty discontinuous Galerkin methods for second order elliptic problems, MAFELAP 2006, Brunel, Uxbridge, June 13 -- 16, 2006.
75. Preconditioning of Discontinuous Galerkin FEM of Second Order Elliptic Problems, 17th International Conference on Domain Decomposition Methods, Strobla, Austria, July 3 -- 7, 2006.
76. Hybridization of the SIPG finite element methods for elliptic problems, International Conference dedicated to the Pioneers of Bulgarian Mathematics, L. Tchakalov and N. Obreshkov, Sofia, July 8-10, 2006.
77. Discontinuous Galerkin FEM for second order elliptic problems and their preconditioning, Int. Conference on Numerical Methods and Application, Borovetz, August 19 -- 23, 2006
78. Discontinuous Galerkin FEM for second order elliptic problems, 3d International Conference Computational Methods in Applied Mathematics: CMAM-3 , June 25 - 30, 2007, Minsk, Belarus
79. Error control and a posteriori error analysis in finite volume methods for convection-diffusion problems, 33rd Conference Applications of Mathematics in Engineering and Economics: AMEE'07, June 8 - 14, 2007, Sozopol, Bulgaria.
80. Hybridization of FE approximations of elliptic problems with applications to discontinuous Galerkin methods, Sixth International Conference on Large Scale scientific computations, June 5-9, 2007, Sozopol, Bulgaria.
81. Error control and a posteriori error analysis in finite volume methods for convection-diffusion problems, 33rd Conference Applications of Mathematics in Engineering and Economics: AMEE'07, June 8 - 14, 2007, Sozopol, Bulgaria.
82. Discontinuous Galerkin FEM for second order elliptic problems, 3d International Conference Computational Methods in Applied Mathematics: CMAM-3 , June 25 - 30, 2007, Minsk, Belarus
83. FEM for second order elliptic problems, Conference honoring James Bramble -- Half a Century in Mathematics, College Station, May 2 - 3, 2008.
84. Hybridization of FEM for second order elliptic problems, Second FEMTEC Conference 2009 Granlibakken Conference Center, Lake Tahoe, January 5 - 9, 2009

Invited Colloquia and Seminars:

1. Seminar on Comput. Mathematics, Inst. of Appl. Mathematics, University of Tbilisi, May 11, 1971 (Prof. I. Vekua).
2. Seminar on Comput. Mathematics, Institute of Cybernetics, Ukrainian Academy Sci., Kiev, May 23, 1973 (Prof. I. Molchanov).
3. Seminar on Appl. Mathematics, Inst. of Appl. Math., Uzbek Acad. of Sci., Tashkent, October 14, 1977 (Prof. K.Kabulov).
4. Seminar on Comput. Mathematics, Computing Center of Siberian Branch of USSR Acad. Sci., Novosibirsk, October 27, 1978 (Prof. G. Marchuk).
5. Seminar on Computational Methods in Mathematical Physics, JINR, Dubna, November 12, 1980 (Prof. E. Zidkov).
6. Seminar on Computational Mathematics, Department of Comput. Mathematics, Acad. Sci., USSR, Moscow, April 24, 1981 (Prof. V. Voevodin and Prof. N. Bahvalov).
7. Seminar on Computational Mathematics, Moscow University, Moscow, April 25, 1981 (Prof. A. Samarskii).
8. Seminar of Approximation Theory, Inst. Mathematics, Bulg. Acad. Sci., Sofia, January 14, 1982 (Prof. Bl. Sendov).
9. Seminar on Comput. Mathematics, Inst. of Appl. Mathematics, University of Tbilissi, April 20, 1983 (Prof. G. Meladze).
10. Seminar on Appl. Mathematics, Technical University of Prague, Prague, September 12, 1984 (Prof. J. Polasek).
11. Seminar on Mathematical Analysis, University of Darmstadt, November 12, 1984 (Prof. W. Wendland).
12. Seminar on Numerical Analysis, University of Goteborg, June 2, 1986 (Prof. V. Thomee).
13. Seminar on Numerical Analysis, University of Goteborg, June 9, 1986 (Prof. V. Thomee).
14. Seminar on Computational Methods, Computing Center of the Siberian Branch of the Acad. Sci., USSR, Novosibirsk, July 5, 1986 (Prof. V. Il'in).
15. Seminar of Numerical Analysis, University of Wien, October 10, 1986 (Prof. H. Stetter).
16. Seminar on Approximation Theory, Texas A M University, College Station, April 15, 1987 (Prof. C. Chui).
17. Seminar on Appl. Mathematics, University of Wyoming, Laramie, October 1, 1987 (Prof. R. Ewing).
18. Seminar on Numerical Analysis Group, University of Colorado, Denver, December 2, 1987 (Prof. McCormick).
19. Seminar on Appl. Mathematics, University of Wyoming, Laramie, January 14, 1988 (Prof. R. Ewing).
20. Seminar on Numerical Analysis, University of Wisconsin, Madison, March 27, 1988 (Prof. S. Parter).
21. Seminar on Numerical Analysis, Purdue University, West Lafayette, May 9, 1988 (Prof. J. Douglas).
22. Seminar on Computational Fluid Dynamics, University of Colorado, Boulder, June 2, 1988 (Prof. K. Gustafsson).
23. Seminar on Computational Mechanics, Texas University, Austin, July 11, 1988 (Prof. G. Carey).
24. Seminar on Numerical Analysis, Cornell University, Ithaca, July 24, 1988 (Prof. J. Bramble).
25. Seminar on Numerical Analysis, University of Goteborg, November 7, 1988 (Prof. V. Thomee).
26. Seminar on Numerical Linear Algebra, University of Linkoping, November 10, 1988 (Prof. A.Bjorck).
27. Seminar on Mathematical Analysis, University of Gent, Gent, November 17, 1988 (Dr. Van Keer).
28. Seminar on Computational Mechanics, University of Brussels, Brussels, November 18, 1988 (Prof. De Wilde).
29. Seminar on Structural Mechanics, Democritus University of Thrace, Xanthi, January 17, 1989 (Prof. A. Liolios).
30. Seminar on domain decomposition and finite element methods, University of Wyoming, Laramie, April 7,1989 (Prof.R.Ewing)
31. Seminar on local refinement technique, Colorado University, Denver, April 8, 1989 (Prof. S. McCormick)
32. Seminar on Mathematical Physics, Ohio State University, Columbus, April 12, 1989 (Prof. G. Forest)
33. Seminar on computational mathematics, Dept. on Comput. Math., Acad. Sci. USSR, Moscow, December 12, 1989 (Prof. Yu.Kuznetsov).
34. Seminar on Numerical Methods, Moscow State University,Moscow, December 15, 1989 (Prof. A.Samarskii)
35. Seminar on Numerical Analysis, Siberian Branch of the Acad. Sci. of USSR, Novosibirsk, May 31, 1990 (Prof. V.Il'in)
36. Seminar on Computational Fluid Mechanics, University of Texas at Austin, July 26, 1990 (Prof. G. Carey)
37. CMA Advanced Computational Seminar, Australian National University, Canberra, November 19, 1990 (Prof. F.de Hoog)
38. Colloquium of Department of Mathematics, Texas A&M University, College Station, March 11, 1992 (Prof. B. Rundell)
39. Seminar on Partial Differential Equations, Texas A&M University, College Station, March 12, 1992 (Prof. B. Rundell)
40. Seminar on Numerical Analysis, Rice University, Houston, November 21, 1992 (Prof. M. Wheeler)
41. Colloquium of Numerical Analysis Group, University of Colorado at Denver, March 16, 1993 (Prof. S. McCormick)
42. Seminar on Applied and Computational Mathematics, University of Houston, April 23, 1993 (Prof. R. Scott)
43. Seminar on Applied mathematics, Inst. of Mathematics and Inst. of System Sciences, Academia Sinica, Beijing, July 22, 1993 (Prof. S. Shao and Prof. Q. Lin)
44. Seminar on Numerical Analysis, Institute of System Sciences, Academia Sinica, Beijing, July 27, 1993 (Prof. Q. Lin)
45. Seminar on Numerical Analysis, Institute of System Sciences, Academia Sinica, Beijing, July 28, 1993 (Prof. Q. Lin)
46. Seminar on Numerical Analysis, Institute of System Sciences, Academia Sinica, Beijing, July 29, 1993 (Prof. Q. Lin)
47. Seminar on Numerical Analysis, Rice University, Houston, Texas, March 27, 1995 (Prof. M. Wheeler)
48. Seminar on SApplied Mathematics, Colorado School of Mines, Golden, Colorado, March 30, 1995 (Prof. G. Fearweather)
49. Seminar on Numerical Analysis, INRIA, Roquencourt, Le Chesnay, May 30, 1995 (Prof. Le Tallec)
50. Seminar on Numerical Analysis, Australian National University, Canberra, Australia, July 10, 1995 (Prof. M. Osborn)
51. Seminar on Numerical Analysis, Southern Methodist University, Dallas, Texas, November 30, 1995 (Prof. G. Reddien)
52. Seminar on Numerical Analysis, University of Texas at Arlington, Arlington, Texas, December 1, 1995 (Prof. G. Fix)
53. Seminar on Numerical Analysis and Differential equations, Duke University, Durham, North Carolina, December 9, 1996 (Prof. J. Trangenstein)
54. Seminar on Numerical Analysis, University of Goteborg and Chalmers University, Sweden, February 6, 1998 (Prof. V. Thomee)
55. Seminar on Applied and Computational Mathematics, Mittag-Lefller Mathematical Institute, Stockholm, February 19, 1998 (Prof. V. Thomee and Prof. O. Widlund)
56. Seminar on Computational Mathematics, University of Linkoping, Sweden, February 27, 1998 (Prof. A. Bork and Prof. L. Hedberg)
57. Colloquium of the Texas Institute of Computational Mathematics, University of Texas at Austin, March 31, 1998 (Prof. M. Wheeler and Prof. L. Demkowicz)
58. Semnar on Applied Mathematics, University of Stuttgart, Germany, April 21, 1998 (Prof. W. Wendland)
59. Seminar on Numerical Analysis, University of Augsburg, Germany, April 23, 1998 (Prof. R. Hoppe)
60. Colloquium on Applied Scientific Computing, Lawrence Livermore National Laboratory, California, June 29, 1998 (Dr. S. Ashby)
61. Colloquium on Applied Scientific Computing, Lawrence Livermore National Laboratory, California, July12, 1999 (Dr. S. Ashby)
62. Seminar on Numerical Analysis, University of Houston, November 4, 1999.
63. Seminar on Numerical Analysis, University of Pittsburgh, November 2, 2000.
64. Seminar on Numerical Analysis, University of Linz, Austria, June 24, 2003.
65. Seminar on Numerical Analysis, I.N. Vekua Institute of Applied Mathematics, Tbilisi University, Georgia, March 17, 2004.
66. Seminar on Numerical Analysis, Department of Mathematics, Pennstate University, May 3, 2004.
67. Colloquium of I.N. Vekua Institute of Applied Mathematics, Tbilisi University, Georgia, March 17, 2004.
68. Department of Mathematics, Pennstate University, May 3, 2004
69. Colloquium of the Intst. of Mathematics, Bulgarian Academy opf Sciences, March 21, 2006.
70. Department of Mathematics, Sofia University, Bulgaria, April 19, 2006
71. Simulation in Technology Center, University of Heidelberg, Germany, June 27, 2006
72. Department of Mathematics, University of Saarbrucken, Germany, July 20, 2006
73. Numerical Analysis Seminar, Texas A&M University, Math. Dept., September 20, 2006
74. Colloquium of BICAM, Brunel University, England, May 30, 2007
75. Numerical Analysis Seminar, University of Crete, Greece, June 5, 2008
76. Numerical Analysis Seminar, ITWM, Germany, July 2, 2008

Classes and Student Seminars:

1. Seminars on Calculus, Sofia University, 1968.
2. Seminars on Ordinary Differential Equations, Sofia University, 1968.
3. Seminars on Numerical Analysis, Moscow University, 1971.
4. Seminars on Numerical Analysis, Sofia University, 1973-82.
5. Lectures on Numerical Analysis II, Sofia University, 1982-1991.
6. Lectures on Numerical Methods for Partial Differential Equations, Technical University at Sofia, 1975-1977.
7. Lectures on Finite Difference Methods, Sofia University, 1974-80.
8. Lectures on Finite Elements, Sofia University, 1980-1991.
9. Lectures on Numerical Methods, Technical University at Sofia, 1976-79.
10. Lectures on Numerical Linear Algebra, University of Wyoming, 1987.
11. Lectures on Numerical Analysis, University of Wyoming, 1988, 1992
12. Lectures on Methods of Applied Mathematics, University of Wyoming, 1988, 1991
13. Lectures on Ordinary Differential Equations, University of Wyoming, 1991.
14. Research Seminar on Numerical Analysis, Inst. Mathematics, Bulg. Acad. Sci., 1977-1991
15. Research Seminar on Numerical Analysis, Department of Mathematics, University of Wyoming, 1992.
16. Lectures on Higher Math. for Physisists and Engns, (Texas A&M University, MATH 602), Fall 1992, 1993, 1994, 1996, 1999, and Spring 1993.
17. Lectures on Numerical Analysis, (Texas A&M University, MATH 609), Spring 1993, Fall 1993, 1994, 1995, 1997, 2000, 2002, 2006, 2007.
18. Lectures on Numerical analysis (Texas A&M University, Math 417), Summer 1994, Fall 1997, Fall 2007
19. Lectures on Numerical Methods for Partial Differential Equations (Texas A&M University, MATH 610), Spring 1994, 1996, 2001, 2003, 2007.
20. Lectures on Iterative Technique (Texas A&M University, MATH 639), Fall 1994 and Spring 2000.
21. Seminar on Analysis (Texas A&M University, MATH 663), Summer 1996, Fall 2000.
22. Special Topics Course: Numerical Methods and Algorithms (Texas A&M University, MATH 663), Fall 2000.
23. Special Topics Course: Introduction to Scientific Computing (Texas A&M University, MATH 663), Spring 2001.
24. Special Topics Course: Advanced Topics in Finite Element Method, (Sofia University, Bulgaria), Spring 2006,
25. Lectures on Ordinary Differential Equations, (Texas A&M University, MATH308), Spring 1997, Fall 1999.
26. Lectures on Calculus III, (Texas A&M University, MATH251), Fall 2002, 2003, 2004, 2006, Spring 2005
27. Research Seminar on Numerical Analysis, Department of Mathematics, Texas A&M University, 1992-1995.

Supervision of Ph. D. Thesis (see, Mathematical Geaneology Project):

1. E. Varbanova, defended 1981.
2. S. Margenov, defended 1984.
3. A. Andreev, defended 1985.
4. M. El Hatri, defended 1985.
5. L. Vulkov, defended 1988.
6. A. Pehlivanov, defended 1989.
7. N. Kumanov, defended 1991.
8. S. Petrova, defended 1993.
9. I. Michev, defended Spring 1996.
10. S. Maliassov, defended Spring 1996.
11. T. Dimov, defended Spring 1999.
12. V. Kantchev, defended Spring 1999.
13. H. Huang, defended Fall 1999.
14. S. Tomov, defended Spring 2002.
15. V. Ginting, defended Spring 2004.
16. V. Dobrev, defended Spring 2007.

Program, Scientific, and Advisory Committees:

1. Program Committee 1st Conference on Numerical Methods and Applications, Sofia, 1984, Chairman.
2. Program Committee, conference on Optimal Algorithms, Blagoevgrad, 1986.
3. Program Committee, 3rd Conference on Differential Equations and Applications, Russe, 1985.
4. Program Committee, 2nd Conference on Numerical Methods and Applications, Sofia, 1988, Chairman.
5. Advisory Scientific Committee, 9th Conference on BEM, Stuttgart, 1987.
6. Scientific Program Committee, 4th Conference on Differential Equations and Applications, Russe, 1989.
7. Program Committee, Conference on Inverse Problems and Integral Equations, Varna, 1989.
8. Program Committee, Conference on Optimal Algorithms, Varna, 1989.
9. Organizing Committee, Summer School on Appl. of Mathematics in Technique, 1981, 1984, 1986, 1988, 1989, 1990
10. Organizing Committee, Summer Schools on Parallel Computer Architectures and Algorithms, Primorsko, 1987, Chairman.
11. Semester on Numerical analysis and Mathematical Medelling in Stefan Banach International Mathematical Center, Warsaw, March - May, 1991, Member of the Organizing Committee.
12. International Conference on Hydrodynamics of Technological Processes for material Production, Kazanlak, August 27-31, 1991, Member of the Organizing Committee.
13. Program Committee, 3-rd Conference on Numerical Methods and Applications, Sofia, August 22-27, 1994, Member of the International Program Committee.
14. PARCELLA 94, Sixth International Workshop on Parallel Processing, Potsdam, September 21 - 23, 1994, Member of the International Programme Committee.
15. Texas Finite Element Circus (Rodeo), College Station, Texas, March 3-4, 1995, Organizer
16. Mathematical Modeling and Computational Experiment, An International Journal, 1995-present
17. Optimization of the Finite Element Approximations, St. Petersburg, Russia, June 25 - 29, 1995, Member of the Scientific Committee
18. Third U.S. National Congress on Computational Mechanics, Dallas, Texas, June 12 - 14, 1995, Special Session Organizer
19. First European Conference on Numerical Analysis, ENUMATH'95, Paris, September 18-22, 1995, Member of the Scientific Committee
20. Iternational Conference on Finite Element Methods: Superconvergence, Post-Processing and a Posteriori Estimates, Jyvaskyla, Finland, July 1-4, 1996, Member of the Scientific Committee
21. PARCELLA 96, Seventh International Workshop on Parallel Processing, Potsdam, September 18 - 21, 1996, Member of the International Programme Committee.
22. Third IMACS International Symposium on Iterative Methods in Scientific Computation, Laramie, Wyoming, July 16 - 19, 1997, Member of the International Programme Committee.
23. Second European Conference on Numerical Analysis, ENUMATH'97, Heidelberg, September 18-22, 1997, Member of the Scientific Committee
24. ENUMATH'97, The Second European Conference on Numerica Mathematics and Advanced Applications, Heidelberg, Germany, September, 1997, special sessionon "Least-Squares Methods" organizer.
25. Member of the Program Committee: First International Conference on Finie Difference Methods, Theory and Applications , Russe, Bulgaria, August 18-22, 1997
26. Second International Conference on Finie Difference Methods; Theory and Applications , Minsk, Belarus, July 6-9, 1998, Member of the Program Committee:
27. Fourth International Conference on Numerical Methods and Applications, Sofia, Bulgaria, August 19-23, 1998, Member of the Program Committee
28. Member of WG 2.5 Numerical Software IFIP (International Federation for Information Processing), 1988-present.
29. A special session on "Least-Squares Methods" organizer: ENUMATH'97, The Second European Conference on Numerical Mathematics and Advanced Applications, Heidelberg, Germany, September, 1997.
30. Member of the Program Committee: Summer School on Solution Methods for Singularly Perturbed Problems, August 26-31, 1998, Lozenetz, Bulgaria.
31. Member of the Program Committee Second Int. Workshop on Large Scale Scientific Computing, June 2-6, 1999, Sozopol, Bulgaria.
32. Member of the Program Committee: Third International Conference on Finite Difference Methods; Theory and Applications, Palanga, Lithuania, September 1-4, 2000.
33. Co-organizer: Workshop on Superconvergence in Finite Element Method, March 20 - 31, 2000, Mathematical Science Research Institute, Berkeley, CA.
34. Co-organizer: AMS-IMS-SIAM Summer Research Conference on Fluid Flow and Transport in Porous Media: Mathematical and Numerical Treatment, June 17 - 22, 2001, Mount Holyoke College, South Hadley, Massachusetts.
35. Member of the Program Committee: International Conference on Preconditioning Methods for Optimal Control and Constrained Optimization (PMOCCO), October 24-26, 2002, Nijmegen, The Nethrlands
36. Member of the Program Committee: Third International Conference on Numerical Methods and Applications, August 20-24, 2002, Borovetz, Bulgaria.
37. Member of the Program Committee: Third Int. Conference on Finite Volume for Complex Applications, June 24-28, 2002, Porquerolles, France.
38. Member of the Program Committee: Fourth Int. Conference on Finite Volume for Complex Applications, July 24-28, 2005, Marakesh, Morocco.
39. Organizer: Miniworkshop on Discontinuous Galerkin Methods, RICAM Special Semester on Computationla Mechanics, November 29, 2005, Linz, Austria.
40. Member of the Program Committee: Int. Conference dedicated to the Pioneers of Bulgarian Mathematics L. Tchakalov and N. Obreshkov, Sofia, July 8-10, 2006.
41. Co-organizer: IMACS conference on iterative methods, Texas A&M, November 15-17, 2006.
42. Co-organizer: Conference celebrating the 60th birthday of Professor Richard D. Ewing, Texas A&M, November 17-18, 2006.
43. Member of the Program Committee: Fourth International Conference on Numerical Methods and Applications, Sofia, Bulgaria, August 19-23, 1998
44. Member of the Program Committee: 6th International Conference on Large-Scale Scientific Computations, June 5-9, 2007, Sozopol

Grants and Contracts:

1. Numerical modelling of heat conduction in ingot steel casting, Contract No 77-440-0093 with the Institute of Material Sciences and Metal Technology, Bulgarian Acad. Sci., 1977-1979.
2. Computing of some crystalization processes in casting of nitrogen steel, Contract No 80-440-0144 with NPO Techmet, 1980-1981, PI.
3. Numerical methods for PDE's, Joint Resaerch Progect with the Department of Cybernetics and Computational Mathematics, Moscow State University, 1981-1993, PI.
4. Computer methods and packages for solving problems of the mathematical physics, Joint Research Project with the Siberian Branch of the Academy of Sciences of USSR, 1981-1990, Co-PI.
5. Computing some heat processes in steel casting technology, Contract No 83-440-0195 with The Institute of Material Sciences and Metal Technology, Bulgarian Acad. Sci., 1983-1986, PI.
6. Mathematical modeling of nonisothermal fluid flow in porous media, Research project with Institute of Geology of Bulgarian Academy of Sciences, 1982-83, Investigator.
7. Mathematical and numerical modeling of the nonisothermal anomaly of the "Erma River" area, Committee of Geology and Mineral Resources of Bulgaria, 1983-1985, Investigator.
8. Superconvergence in the finite element method, Grant No 55 26-3-1987 with the Bulgarian Ministry of Science and Higher Education, 1987-1992, PI.
9. Parallel methods for partial differential equations, Grant No 938-21-06-88 with the Bulgarian Ministry of Science and Higher Education, 1988-1991, PI.
10. Efficient local refinement tehniques for convection-diffusion problems, NSF, Grant No INT 89-14472, 1990-1994, Co-PI.
11. Differential equations and numerical methods, Research project No 100-008 with the Presidium of the Bulgarian Academy of Sciences, 1988-1993, PI.
12. Combinatorial algorithms and parallel computations, Research project No 100-014 with the Presidium of the Bulgarian Academy of Sciences, 1988-1993, PI.
13. Partnership in Computational Science, DOE, DE-FG05-92ER25143, 1994-1995, Investigator.
14. Domain decompositiom and multilevel techniques in large scale parallel computing, US-France joint research project, NSF-INRIA, 1994-1997, Investigator.
15. Wavelet Gelerkin methods and muliresolution analysis in computational mechanics, NASA, NAG-1-1618, May 1994 - Oct. 1996, Co-PI.
16. Partitioning algorithms and their application to massively parallel computations of muliphase fluid flows in porous media, EPA, October 1996 - July 2000, Co-PI.
17. Construction of accurate, robust, and efficient numerical techniques for partial differential equations, NSF-DMS-9626567, August 15, 1996 - July 31, 1999, Co-PI.
18. Mathematical Sciences Computing Research Environments NSF-DMS-97-07930 (a SCREMS grant for equipment) May 1, 1997 to April 31, 1998, Co-PI.
19. Numerical methods for PDEs in large scale scientific computings, Cost reimbusable contract for a sabatical leave to Lawrence Livermore National Laboratory, September 1, 1998 to July 31, 1999, PI.
20. Construction of accurate, robust, and efficient numerical techniques for partial differential equations, DMS-9973328, July 1, 1999 to June 30, 2002, Co-PI.
21. New spacial discretization techniques for neutral-particle transport calculations, LANL-DOE, February 29, 2000 to May 31, 2001, Co-PI.
22. Study and testing of numerical methods for differential equations, Contract with the Univwersity of Californbia, Lawrence Livermore National Laboratory, June 29, 2000 to October 31, 2000, Co-PI.
23. Numerical methods and their application to computer simulation of flows in underground reservoirs: An international collaboration with PR China, NSF-DMS-9901498, December 15, 1999 to December 15, 2002, Co-PI.
24. Non-conforming finite elements: mesh generation, adaptivity and related algebraic multigrid and domain decomposition methods in massively parallel computer environment, Contract with the Univwersity of Californbia, Lawrence Livermore National Laboratory, May 31, 2001 to December 31, 2001, Co-PI.
25. NSF-DEIA "Predictive Contaminant Tracking Using Dynamic Data Driven Application Simulation (DDDAS) Techniques" (Collaborative Research: ITR/AP Grant) NSF-ITR-0218229, September 10, 2002 to September 15, 2005, Co-PI.
26. LLNL-DOE, "Adaptivity and related algebraic multigrid and non-conforming domain decomposition methods in a massively parallel computing environment", Contract with the University of California, Lawrence Livermore National Laboratory, January 1, 2003 to June 30, 2003, Co-PI.
27. CRDF-GRDF, "Development and research of deterministic and stochastic mathematical models for control and management of pollution level of fluvial waters and their realization by application package", Collaborative research project funded by U.S. Civilian Research & Development Foundation (CRDF) and the Georgian Research & Development Foundation (GRDF), October 1, 2002 - August 30, 2004, PI.
28. R.D. Lazarov and J.E. Pasciak, LLNL-DOE, "Construction and preconditioning of finite element approximations of mixed problems," Contract with the University of California, Lawrence Livermore National Laboratory, May 30, 2005 -- September 31, 2005, Co-PI
29. Y. Efendiev, R.E. Ewing, and R. Lazarov, NSF-DEIA, "Collaborative Research: Adaptive Data-Driven Sensor Configuration, Modeling, and Deployment for Oil, Chemical, and Biological Contamination near Coastal Facilities," (Collaborative Research: ITR/AP Grant), October 1, 2005 -- September 30, 2006, Co-PI.
30. R.D. Lazarov, Fraunhofer Society, Institute for Industrial Mathematics (Germany): "Numerical methods for problems in poroelasticity and their applications," December 1, 2005 -- July 30, 2006, PI.
31. NSF-DMS, "Discontinuous Galerkin Methods for PDEs with Heterogeneous Coefficients", NSF-DMS-0713829, September 1, 2007 - August 31, 2010, Co-PI.
32. LLNL-DOE, "Comutational issues in neutron transport", Contract with the University of California, Lawrence Livermore National Laboratory, May 30, 2007 to December 31, 2007, Co-PI.