S. Trewin. Proceedings of the 2006 international cross-disciplinary workshop on Web accessibility (W4A): Building the mobile web: rediscovering accessibility?, page 109--112. Edinburgh, U.K., ACM, (2006)
A. Oniszczak, and I. MacKenzie. Proceedings of the third Nordic conference on Human-computer interaction, page 101--104. New York, NY, USA, ACM, (2004)