G. Schröder, M. Thiele, and W. Lehner. Proceedings of the Workshop on User-Centric Evaluation of Recommender Systems and Their Interfaces, page 78--85. Chicago, USA, CEUR-WS, (October 2011)
A. Schein, A. Popescul, L. Ungar, and D. Pennock. Proceedings of the 25th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval, page 253--260. New York, NY, USA, ACM, (2002)