@Inproceedings{Lutz-Walther-Wolter-07,
  author    = {Carsten Lutz and Dirk Walther and Frank Wolter},
  title     = {Conservative Extensions in Expressive Description Logics.},
  booktitle = {Proceedings of IJCAI 2007: the 20th International Joint
               Conference on Artificial Intelligence, Hyderabad, India,
               January 6--12, 2007},
  editor    = {Manuela M. Veloso},
  year      = {2007},
  pages     = {453--458},
  publisher = {AAAI Press},
}