R. Almeida, und V. Almeida. WWW '04: Proceedings of the 13th international conference on World Wide Web, Seite 413--421. New York, NY, USA, ACM Press, (2004)
C. Danis, F. Viegas, M. Wattenberg, und J. Kriss. CHI '08: Proceeding of the twenty-sixth annual SIGCHI conference on Human factors in computing systems, Seite 275--284. New York, NY, USA, ACM, (2008)
J. Freyne, R. Farzan, P. Brusilovsky, B. Smyth, und M. Coyle. IUI '07: Proceedings of the 12th international conference on Intelligent user interfaces, Seite 52--61. New York, NY, USA, ACM Press, (2007)