@InProceedings{delsch98a,
  author = 	 "J. Delgrande and T. Schaub",
  title = 	 "Reasoning with Sets of Preferences in Default Logic",
  booktitle = 	 "Pacific Rim International Conference on Artificial Intelligence",
  pages =	 "134-145",
  year =	 1998,
  editor =	 "H.-Y. Lee and H. Motoda",
  volume =	 1531,
  series =	 lnai,
  publisher =	 springer
}