B. Boser, I. Guyon, and V. Vapnik. COLT '92: Proceedings of the fifth annual workshop on Computational
learning theory, page 144--152. New York, NY, USA, ACM Press, (1992)
M. Czerwinski, E. Horvitz, and S. Wilhite. CHI '04: Proceedings of the SIGCHI conference on Human factors in computing systems, page 175--182. New York, NY, USA, ACM Press, (2004)