@inproceedings{ijcai1991p127,
  title     = {Derivation Procedures for Extended Stable Models},
  author    = {Pereira, Luís Moniz and Aparício, Joaquim Nunes and Alferes, José Júlio},
  booktitle = {Proceedings of the Twelfth International Joint Conference on
               Artificial Intelligence, {IJCAI-91}},
  publisher = {International Joint Conferences on Artificial Intelligence},
  editor    = {John Mylopoulos and Ray Reiter},
  pages     = {863--868},
  year      = {1991},
  month     = {8},
  note      = {Logic Programming},
  url       = {https://ijcai.org/proceedings/1991/127},
}