E. Agichtein, E. Brill, und S. Dumais. SIGIR '06: Proceedings of the 29th annual international ACM SIGIR conference on Research and development in information retrieval, Seite 19--26. New York, NY, USA, ACM Press, (2006)
R. White, I. Ruthven, und J. Jose. SIGIR '05: Proceedings of the 28th annual international ACM SIGIR conference on Research and development in information retrieval, Seite 35--42. New York, NY, USA, ACM Press, (2005)