H. Yu, J. Han, and K. Chang. Proceedings of the Eighth ACM SIGKDD International Conference on Knowledge Discovery and Data Mining, page 239--248. New York, NY, USA, ACM, (2002)
M. Anderka, B. Stein, and N. Lipka. Proceedings of the 20th ACM international conference on Information and knowledge management, page 2313--2316. New York, NY, USA, ACM, (2011)
R. Curry, and M. Heywood. Proceedings of the IEEE International Conference on
Systems, Man, and Cybernetics, page 1938--1945. Montreal, IEEE Press, (7-10 October 2007)