M. Goodrich. Proceedings of the Twenty-first Annual ACM-SIAM Symposium on Discrete Algorithms, page 1262--1277. Philadelphia, PA, USA, Society for Industrial and Applied Mathematics, (2010)
T. Hofmann, J. Puzicha, and M. Jordan. Proceedings of the 1998 conference on Advances in neural information processing systems II, page 466--472. Cambridge, MA, USA, MIT Press, (1999)
S. Robertson, H. Zaragoza, and M. Taylor. CIKM '04: Proceedings of the thirteenth ACM international conference on Information and knowledge management, page 42--49. New York, NY, USA, ACM, (2004)