T. Sakai, and K. Spärck Jones. Proceedings of the 24th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval, (2001)
T. Sakai, and K. Sparck-Jones. SIGIR '01: Proceedings of the 24th annual international ACM SIGIR conference on Research and development in information retrieval, page 190--198. New York, NY, USA, ACM Press, (2001)