L. Lucignano, F. Cutugno, S. Rossi, and A. Finzi. Proceedings of the 15th ACM on International Conference on Multimodal Interaction, page 197–204. New York, NY, USA, Association for Computing Machinery, (2013)
K. Kamei, K. Shinozawa, T. Ikeda, A. Utsumi, T. Miyashita, and N. Hagita. Proceedings of the 12th International Conference on Multimodal Interfaces and the 7th Workshop on Machine Learning for Multimodal Interfaces (IMCI-MLMI 2010), Beijing, China, page 19:1--19:8. (2010)