Y. Wu, and T. Huang. Proceedings of the International Gesture Workshop on Gesture-Based Communication in Human-Computer Interaction, page 103--115. London, UK, Springer-Verlag, (1999)
M. Pantic, A. Pentland, A. Nijholt, and T. Huang. ICMI '06: Proceedings of the 8th International Conference on Multimodal
Interfaces, page 239--248. New York, NY, USA, ACM Press, (2006)