E. Voorhees. Proceedings of the 16th annual international ACM SIGIR conference on Research and development in information retrieval, page 171--180. New York, NY, USA, ACM, (1993)
M. Sanderson. Proceedings of the 17th annual international ACM SIGIR conference on Research and development in information retrieval, page 142--151. New York, NY, USA, Springer-Verlag New York, Inc., (1994)
H. Schütze, and J. Pedersen. Proceedings of the 4th Annual Symposium on Document Analysis and Information Retrieval, page 161--175. Las Vegas, USA, (1995)
D. Lewis. Proceedings of ECML-98, 10th European Conference on Machine Learning, 1398, page 4--15. Chemnitz, DE, Springer Verlag, Heidelberg, DE, (1998)