@inproceedings{ijcai2003p52,
  title     = {Keys, Nominals, and Concrete Domains},
  author    = {Lutz, Carsten and Areces, Carlos and Horrocks, Ian and Sattler, Ulrike},
  booktitle = {Proceedings of the Eighteenth International Joint Conference on
               Artificial Intelligence, {IJCAI-03}},
  publisher = {International Joint Conferences on Artificial Intelligence},
  editor    = {Georg Gottlob},
  pages     = {349--353},
  year      = {2003},
  url       = {https://ijcai.org/proceedings/2003/52},
}