1. Bashyal, S., Venayagamoorthy, G.K.: Recognition of facial expressions using Gabor wavelets and learning vector quantization. Engineering Applications of Artificial Intelligence 21(7), 1056–1064 (2008)
2. van den Broek, E., Janssen, J., Westerink, J., Healey, J.: Prerequisites for affective signal processing (asp). In: Encarnao, P., Veloso, A. (eds.) Biosignals 2009: Proceedings of the Second International Conference on Bio-Inspired Systems and Signal Processing, pp. 426–433. INSTICC Press, Portugal (2009)
3. Ekman, P., Friesen, W.V., Hager, J.C.: Facial Action Coding System [E-book]. Research Nexus, Salt Lake City (2002)
4. Ekman, P.: About brows: emotional and conversational signals. In: von Cranach, M., Foppa, K., Lepenies, W., Ploog, D. (eds.) Human Ethology: Claims and limits of a new discipline, pp. 169–248. Cambridge University Press (1979)
5. Gritti, T., Shan, C., Jeanne, V., Braspenning, R.: Local features based facial expression recognition with face registration errors. In: 8th IEEE International Conference on Automatic Face Gesture Recognition, FG 2008, pp. 1–8 (2008)