H. Hirsh, and D. Kudenko. Proceedings of the Fourteenth National Conference on Artificial Intelligence, page 384-389. AAAI Press / The MIT Press, (1997)
B. Grossof, I. Horrocks, R. Volz, and S. Decker. Proceedings of the 12th International World Wide Web Conference (WWW 2003), Budapest, Hungary, (May 2003)
F. Baader, S. Brand, and C. Lutz. International Joint Conference on Artificial Intelligence (IJCAI) 2005, page 364--369. Morgan-Kaufmann Publishers, (2005)
I. Horrocks, O. Kutz, and U. Sattler. Proceedings of the 10th International Conference on Principles of Knowledge Representation and Reasoning, page 57-67. AAAI Press, (2006)