S. Oviatt, A. Cohen, and N. Weibel. Proceedings of the 15th ACM on International Conference on Multimodal Interaction, page 563--568. New York, NY, USA, ACM, (2013)Workshop.
G. Di Fabbrizio, J. Wilpon, and T. Okken. Proceedings of the 11th International Conference on Multimodal Interfaces and the 6th Workshop on Machine Learning for Multimodal Interfaces (ICMI-MLMI '09), Cambridge, MA, USA, page 71-78. (2009)