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)
E. Brill, and J. Wu. 36th Annual Meeting of the Association for Computational Linguistics and 17th International Conference on Computational Linguistics, Volume 1, page 191--195. Montreal, Quebec, Canada, Association for Computational Linguistics, (August 1998)