Eva Cerezo Isabelle Hupont Cristina Manresa-Yee Xavier Varona Sandra Baldassarri Francisco J. Perales López Francisco J. Serón Real-Time Facial Expression Recognition for Natural Interaction. 40-47 2007 conf/ibpria/2007-2 IbPRIA (2) http://dx.doi.org/10.1007/978-3-540-72849-8_6 db/conf/ibpria/ibpria2007-2.html#CerezoHMVBLS07