T. LIU, Y. YANG, H. WAN, Q. ZHOU, B. GAO, H. ZENG, Z. CHEN, und W. MA. Special interest tracks and posters of the 14th international conference on World Wide Web, Seite 1106--1107. New York, NY, USA, ACM, (2005)
J. Kubica, A. Moore, J. Schneider, und Y. Yang. Proceedings of the Eighteenth National Conference on Artificial Intelligence, Seite 798--804. AAAI Press/MIT Press, (Juli 2002)
