A. Shepitsen, J. Gemmell, B. Mobasher, and R. Burke. RecSys '08: Proceedings of the 2008 ACM conference on Recommender systems, page 259--266. New York, NY, USA, ACM, (2008)
Y. Zhao, and G. Karypis. CIKM '02: Proceedings of the eleventh international conference on Information and knowledge management, page 515--524. New York, NY, USA, ACM Press, (2002)