S. Shum, E. Motta, and J. Domingue. ECDL '99: Proceedings of the Third European Conference on Research and Advanced Technology for Digital Libraries, page 423--442. London, UK, Springer-Verlag, (1999)
N. Niu, and S. Easterbrook. EA '06: Proceedings of the 2006 international workshop on Early Aspects at ICSE 2006, page 35--42. New York, NY, USA, ACM Press, (2006)
R. Baeza-Yates, P. Boldi, and C. Castillo. SIGIR '06: Proceedings of the 29th annual international ACM SIGIR conference on Research and development in information retrieval, page 308--315. New York, NY, USA, ACM Press, (2006)
G. Feng, T. Liu, Y. Wang, Y. Bao, Z. Ma, X. Zhang, and W. Ma. SIGIR '06: Proceedings of the 29th annual international ACM SIGIR conference on Research and development in information retrieval, page 75--82. New York, NY, USA, ACM Press, (2006)