1. Burns, H., Parlett, J. (eds.): Proceedings of the second intelligent tutoring systems research forum. San Antonio, Tx., April 1989
2. Dede, Christoper: Educational and Social Implications. In: Forester (ed.) 1985
3. Duchastel, Philippe C.: Cognitive Design for Instructional Design. In: Instructional Science 19, pp. 437–444, (1990)
4. Flavell, J. H.: Cognitive Development. Prentice-Hall, N.J., 1977
5. Forester, Tom (ed.) The Information Technology Revolution. Oxford, Basil Blackwell, 1985