R. Jin, L. Si, C. Zhai, und J. Callan. Proceedings of the twelfth international conference on Information and knowledge management, Seite 309--316. New York, NY, USA, ACM, (2003)
M. Claypool, P. Le, M. Wased, und D. Brown. Proceedings of the 6th international conference on Intelligent user interfaces, Seite 33--40. New York, NY, USA, ACM, (2001)