@inproceedings{DBLP:conf/dlog/CaliGL09,
  title = "Tractable Query Answering over Ontologies with Datalog+⁄−",
  author = "Andrea Cal\`{\i} and Georg Gottlob and Thomas Lukasiewicz",
  year = "2009",
  booktitle = "Proceedings of the 22nd International Workshop on Description Logics, DL 2009, Oxford, UK, July 27-30, 2009",
  editor = "Bernardo Cuenca Grau and Ian Horrocks and Boris Motik and Ulrike Sattler",
  publisher = "CEUR-WS.org",
  series = "CEUR Workshop Proceedings",
  url = "http://ceur-ws.org/Vol-477/paper_46.pdf",
  volume = "477",
}