1. Picard, R. (ed.): Affective Computing. The MIT Press, Cambridge (1997)
2. Cornelius, R.R.: Theoretical Approaches to Emotion. In: Cowie, R., Douglas-Cowie, E., Schröder, M. (eds.) Proc. ISCA Workshop on Speech and Emotion, Newcastle, Northern Ireland, pp. 3–10 (2000)
3. Batliner, A., Fischer, K., Huber, R., Spilker, J., Nöth, E.: How to Find Trouble in Communication. Speech Communication 40, 117–143 (2003)
4. Batliner, A., Zeissler, V., Frank, C., Adelhardt, J., Shi, R.P., Nöth, E.: We are not amused - but how do you know? User states in a multi-modal dialogue system. In: Proc. European Conf. on Speech Communication and Technology, Geneva, Switzerland, vol. 1, pp. 733–736 (2003)
5. Batliner, A., Hacker, C., Steidl, S., Nöth, E., Haas, J.: User States, User Strategies, and System Performance: How to Match the One with the Other. In: Proc. of an ISCA tutorial and research workshop on error handling in spoken dialogue systems, Chateau d’Oex, ISCA, pp. 5–10 (2003)