M. Böhmer, B. Hecht, J. Schöning, A. Krüger, and G. Bauer. Proceedings of MobileHCI '11: 13th International Conference on Human Computer Interaction with Mobile Devices and Services, Stockholm, Sweden, page 47-56. (2011)
M. Johnston. 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 47-54. (2009)