S. Bloehdorn, P. Haase, Y. Sure, and J. Völker. Semantic Web Technologies --- Trends and Research in Ontology-Based Systems, chapter 4, John Wiley & Sons, Chichester, West Sussex, UK, (June 2006)
M. Klein, D. Fensel, A. Kiryakov, and D. Ognyanov. Proc. of the 13th European Conf. on Knowledge Engineering and Knowledge Management (EKAW02) (Siguenza, Spain), page 197--212. (2002)
B. Smith, and C. Welty. Proceeding of the 2nd International Conference on Fortmal Ontology and Information Systems (FOIS 2001), Ogunquit, Maine, USA, (2001)
H. Lieberman, D. Smith, and A. Teeters. In Proceedings of the Workshop on Common Sense and Intelligent User Interfaces held in conjunction with the 2007 International Conference on Intelligent User Interfaces (IUI 2007), (2007)
X. Wu, L. Zhang, and Y. Yu. WWW '06: Proceedings of the 15th international conference on World Wide Web, page 417--426. New York, NY, USA, ACM Press, (2006)