M. Tsagkias, M. de Rijke, and W. Weerkamp. Proceedings of the Fourth ACM International Conference on Web Search and Data Mining, page 565--574. New York, NY, USA, ACM, (2011)
S. Jamali, and H. Rangwala. Proceedings of the 2009 International Conference on Web Information Systems and Mining, page 32--38. Washington, DC, USA, IEEE Computer Society, (2009)
M. Saleem. (2006)http://themulife.com/?p=145. Accessed 11-Oct-2008 from its cached copy at http://www.google.com/search?q=cache:Uj2wkQrBeCAJ:www.themulife.com/wp-trackback.php%3Fp%3D145&strip=1.