A. de Assis, M. Danchak, and L. Polhemus. CLIHC '05: Proceedings of the 2005 Latin American conference on Human-computer interaction, page 289--294. New York, NY, USA, ACM Press, (2005)
E. Brown, T. Brailsford, T. Fisher, A. Moore, and H. Ashman. WWW '06: Proceedings of the 15th international conference on World Wide Web, page 327--335. New York, NY, USA, ACM Press, (2006)