B. Dorow, and D. Widdows. Proceedings of the tenth conference on European chapter of the Association for Computational Linguistics - Volume 2, page 79--82. Morristown, NJ, USA, Association for Computational Linguistics, (2003)
W. Xu, X. Liu, and Y. Gong. SIGIR '03: Proceedings of the 26th annual international ACM SIGIR conference on Research and development in informaion retrieval, page 267--273. New York, NY, USA, ACM, (2003)
N. Slonim, and N. Tishby. SIGIR '00: Proceedings of the 23rd annual international ACM SIGIR conference on Research and development in information retrieval, page 208--215. New York, NY, USA, ACM, (2000)