J. Xu, C. Chen, G. Xu, H. Li, und E. Abib. WSDM '10: Proceedings of the third ACM international conference on Web search and data mining, Seite 171--180. New York, NY, USA, ACM, (2010)
E. Agichtein, E. Brill, S. Dumais, und R. Ragno. SIGIR '06: Proceedings of the 29th annual international ACM SIGIR conference on Research and development in information retrieval, Seite 3--10. New York, NY, USA, ACM, (2006)