G. Di Fabbrizio, T. Okken, and J. Wilpon. Proceedings of the 2009 international conference on Multimodal interfaces, page 71--78. New York, NY, USA, ACM, (2009)
M. Annett, and E. Stroulia. CASCON '08: Proceedings of the 2008 conference of the center for advanced studies on collaborative research, page 192--206. New York, NY, USA, ACM, (2008)