@inproceedings{DBLP:conf/pricai/DelgrandeS98,
  title = {Reasoning with Sets of Preferences in Default Logic},
  author = {Delgrande, James P. and Schaub, Torsten},
  booktitle = {{PRICAI}},
  pages = {134--145},
  publisher = {Springer},
  series = {Lecture Notes in Computer Science},
  volume = {1531},
  year = {1998}
}