1. Bartlett, M.S., Donato, G., Movellan, J.R., Hager, J.C., Ekman, P., Sejnowski, T.J.: Face image analysis for expression measurement and detection of deceit. In: Proceedings of the 6th Annual Joint Symposium on Neural Computation (1999)
2. Baum, L.E.: An equality and associated maximization technique in statistical estimation for probabilistic functions of markov processes. Inequalities 3, 1–8 (1972)
3. Belhumeur, P.N., Hespanha, J.P., Kriegman, D.J.: Eigenfaces vs. fisherfaces: Recognition using class specific linear projection. IEEE Transactions on Pattern Analysis and Machine Intelligence 19(7), 711–720 (1997)
4. Chuang, C.-F., Shih, F.Y.: Recognizing facial action units using independent component analysis and support vector machine. Pattern Recognition 39(9), 1795–1798 (2006)
5. Donato, G., Bartlett, M.S., Hager, J.C., Ekman, P., Sejnowski, T.J.: Classifying facial actions. IEEE Transactions on Pattern Analysis and Machine Intelligence 21(10), 974–989 (1999)