D. Carmel, Y. Maarek, M. Mandelbrod, Y. Mass, and A. Soffer. Proceedings of the 26th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval, page 151-158. Toronto, Canada, ACM Press, (July 2003)
S. Cohen, C. Domshlak, and N. Zwerdling. WWW '07: Proceedings of the 16th international conference on World Wide Web, page 1183--1184. New York, NY, USA, ACM, (2007)