P. Li, J. Nie, B. Wang, and J. He. Web Intelligence and Intelligent Agent Technology (WI-IAT), 2012 IEEE/WIC/ACM International Conferences on, 1, page 274-281. (December 2012)
R. Wetzker, C. Zimmermann, C. Bauckhage, and S. Albayrak. WSDM '10: Proceedings of the Third ACM International Conference on Web Search and Data Mining, page 71--80. New York, NY, USA, ACM, (2010)