J. Teevan, C. Alvarado, M. Ackerman, and D. Karger. Proceedings of the SIGCHI Conference on Human Factors in Computing Systems, page 415--422. New York, NY, USA, ACM, (2004)
M. De Choudhury, M. Morris, and R. White. Proceedings of the 32Nd Annual ACM Conference on Human Factors in Computing Systems, page 1365--1376. New York, NY, USA, ACM, (2014)