B. Mehta, and T. Hofmann. Proceedings of the 29th annual German conference on Artificial intelligence, page 244--259. Berlin, Heidelberg, Springer-Verlag, (2007)
J. Basilico, and T. Hofmann. ICML '04: Proceedings of the twenty-first international conference on Machine learning, page 9. New York, NY, USA, ACM, (2004)
T. Hofmann. volume 2003 of Special issue of the SIGIR forum, New York, NY, International Conference on Research and Development in Information Retrieval, ACM Press, (2003)