R. Torres, S. McNee, M. Abel, J. Konstan, and J. Riedl. Proceedings of the 4th ACM/IEEE-CS Joint Conference on Digital Libraries, page 228--236. New York, NY, USA, ACM, (2004)
K. Chandrasekaran, S. Gauch, P. Lakkaraju, and H. Luong. Adaptive Hypermedia and Adaptive Web-Based Systems, volume 5149 of Lecture Notes in Computer Science, Springer, Berlin/Heidelberg, (2008)