E. Horvitz, J. Apacible, and M. Subramani. User Modeling 2005, 10th International Conference, UM 2005, Edinburgh,
Scotland, UK, July 24-29, 2005, Proceedings, volume 3538 of Lecture Notes in Computer Science, Springer, (2005)
R. Boardman, and M. Sasse. Proceedings of the SIGCHI conference on Human factors in computing
systems, CHI, volume 6 of CHI Letters, page 583 - 590. ACM Press, New York, (2004)