R. Agrawal, J. Gehrke, D. Gunopulos, and P. Raghavan. SIGMOD '98: Proceedings of the 1998 ACM SIGMOD International Conference on Management of Data, page 94-105. ACM Press, (1998)
P. Anick, and S. Vaithyanathan. Proceedings of the 20th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval, page 314-323. (1997)
F. Beil, M. Ester, and X. Xu. Proceedings of the Eighth ACM SIGKDD International Conference on Knowledge Discovery and Data Mining, page 436-442. ACM Press, (2002)