M. Pasca, и S. Harabagiu. SIGIR '01: Proceedings of the 24th annual international ACM SIGIR conference on Research and development in information retrieval, стр. 366--374. New York, NY, USA, ACM, (2001)
M. Sokolova, и G. Totkov. CompSysTech '07: Proceedings of the 2007 international conference on Computer systems and technologies, стр. 1--6. New York, NY, USA, ACM, (2007)