@Article{BGH04,
  author = 	 {Wolfgang Bangerth and Marcus Grote and Christel Hohenegger},
  title = 	 {Finite Element Method For Time Dependent Scattering:
                  Nonreflecting Boundary Condition, Adaptivity, and 
                  Energy Decay}, 
  journal = 	 {Comp. Meth. Appl. Mech. Engrg.},
  year = 	 {2004},
  volume =	 {193},
  pages =	 {2453--2482}
}