H. Chen, F. Perich, D. Chakraborty, T. Finin, and A. Joshi. Proceedings of the Third International Joint Conference on Autonomous Agents and Multiagent Systems - Volume 2, page 854--861. Washington, DC, USA, IEEE Computer Society, (2004)
A. Ankolekar, M. Krötzsch, T. Tran, and D. Vrandecic. WWW '07: Proceedings of the 16th international conference on World Wide Web, page 825--834. New York, NY, USA, ACM Press, (2007)