Y. Zhao, и G. Karypis. CIKM '02: Proceedings of the eleventh international conference on Information and knowledge management, стр. 515--524. New York, NY, USA, ACM Press, (2002)
D. Cutting, D. Karger, J. Pedersen, и J. Tukey. Proceedings of the 15th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval, SIGIR'92, стр. 318--329. (1992)