1. Cassell, J., Sullivan, J., Prevost, S., Churchill, E. (eds.): Embodied Conversational Agents. MIT Press, Cambridge (2000)
2. Ruttkay, Z., Doorman, C., Noot, H.: Evaluating ECAs - What and how? In: Proceedins of the AAMAS 2002 Workshop on Embodied conversational agents - let’s specify and evaluate them!, Bologna, Italy (July 2002)
3. Ahlberg, J., Pandzic, I.S., You, L.: Evaluationg MPEG-4 Facial Animation Players. In: Pandzic, I.S., Forchhimer, R. (eds.) MPEG-4 Facial Animation: the standard, implementation and applications, pp. 287–291. Wiley & Sons, Chichester (2002)
4. Eckman, P., Friesen, W.: Manual for the Facial Action Coding Systems. Consulting Psych. Press, Palo Alto (1977)
5. Ferrigno, G., Pedotti, A.: ELITE: A Digital Dedicated Hardware System for Movement Analysis via Real-Time TV Signal Processing. In: IEEE - BME-32, pp. 943–950 (1985)