@inproceedings{DBLP:conf/sebd/CaliGL09,
  title = "A General Datalog-Based Framework for Tractable Query Answering over Ontologies (Extended Abstract)",
  author = "Andrea Cal\`{\i} and Georg Gottlob and Thomas Lukasiewicz",
  year = "2009",
  booktitle = "Proceedings of the 17th Italian Symposium on Advanced Database Systems, SEBD 2009, Camogli, Italy, June 21-24, 2009",
  editor = "Valeria De Antonellis and Silvana Castano and Barbara Catania and Giovanna Guerrini",
  isbn = "978-88-6122-154-3",
  pages = "29-36",
  publisher = "Edizioni Seneca",
  url = "http://www.kr.tuwien.ac.at/staff/lukasiew/sebd09b.pdf",
}