M. Ames, and M. Naaman. CHI '07: Proceedings of the SIGCHI conference on Human factors in computing systems, page 971--980. New York, NY, USA, ACM, (2007)
M. Kellogg Smith. Proceedings of the 17th Annual ASIS&T SIG/CR Classification Research Workshop, November 4, 2006, Austin, Texas, USA, page 1-19. (2006)