1. Anderson J, Boyle C, Farrell, R, Reiser B. Cognitive principles in the design of computer tutors. In: Morris P, ed. Modeling Cognition. New York, USA: John Wiley, 1987.
2. Apple Computer. Knowledge Navigator Video. 1997. Available at(2003-09-13) http://www.billzarchy.com/clips/clips_apple_nav.htm
3. Ayala G, Yano Y. Intelligent agents to support the effective collaboration in a CSCL environment. In: Proceedings of World Conference on Educational Telecommunication (ED-TELECOM?96). Boston, MA, USA: AACE Press, 1996:19?24.
4. Baggetun R, Dolonen J, Dragsnes, S. Designing pedagogical agents for collaborative telelearning scenarios. In: Bjørnestad S, Moe R, Mørch A, Opdahl, eds. Proceedings of the 24th Information Systems Research Seminar in Scandinavia (IRIS?24). Ulvik,Norway: Department of Information Science, University of Bergen, 2001:29?42.
5. Bannon L. Computer-mediated communication. In: Norman DA, Draper SW, eds. User Centered System Design: New Perspectives on Human-Computer Interaction. Hillsdale, NJ, USA: Lawrence Erlbaum, 1986:433?456.