J.  Whitehill, Littlewort, G., Fasel, I., Bartlett, M., and Movellan, J., ?Toward Practical Smile Detection?, IEEE Transactions on Pattern Analysis and Machine Intelligence, vol. 31, no. 11, pp. 2106-2111, 2009.

J.  Whitehill and Movellan, J. R., ?A discriminative approach to frame-by-frame head pose tracking?, in 8th IEEE International Conference on Automatic Face Gesture Recognition, 2008. FG '08, Amsterdam, 2008.