E. Agichtein, E. Brill, и S. Dumais. SIGIR '06: Proceedings of the 29th annual international ACM SIGIR conference on Research and development in information retrieval, стр. 19--26. New York, NY, USA, ACM Press, (2006)
S. Dumais, E. Cutrell, J. Cadiz, G. Jancke, R. Sarin, и D. Robbins. SIGIR '03: Proceedings of the 26th annual international ACM SIGIR conference on Research and development in informaion retrieval, стр. 72--79. ACM Press, (июля 2003)