@article{DBLP:journals/ai/DelgrandeS00,
  title = {Expressing preferences in default logic},
  author = {Delgrande, James P. and Schaub, Torsten},
  journal = {Artif. Intell.},
  number = {1-2},
  pages = {41--87},
  volume = {123},
  year = {2000}
}