A. Weingessel, E. Dimitriadou, and S. Dolnicar. Working Paper 29. SFB ``Adaptive Information Systems and Modeling in Economics and Management Science'', (1999)
R. Torres, S. Mcnee, M. Abel, J. Konstan, and J. Riedl. International Conference on Digital Libraries,Proceedings of the 4th ACM/IEEE-CS joint conference on Digital libraries, (2004)