1. A general psychoevolutionary theory of emotion;R.Plutchik;Emotion: Theory, research and experience: Theories of emotion,1980
2. Afzal, S., & Robinson, P. (2009). Natural affect data: Collecting and anotation in a learning context. In Proceedings of the 3rd International Conference on Affective Computing and Intelligent Interaction Workshop. Amsterdam: ACII.
3. Aleven, V., & Koedinger, K. (2000). Limitation of student control: Do studen know when they need help? In Proceedings of 5th International Conference on Intelligent Tutoring Systems. Academic Press.
4. Alexandar, S., Sarrafzadeh, A., & Hill, S. (2006). Easy with eve: A functional affective tutoring system. In Proceedings of Workshop on Motivational and Affective Issues in ITS. ITS.
5. Ammar, M. B., Neji, M., & Alimi, A. M. (2005). The integration of an emotional system in the intelligent tutoring system. In Proceedings of the 3rd ACS/IEEE Internation Conference on Computer Systems and Applications. ACS/IEEE.