2University of Pittsburgh. An intelligent tutoring system for physics[EB/OL]. http://www. pitt. edu/~vanlehn/andes. html,2003-11-10.
3Vladan Devedzic,Andreas Harrer. Architectural patterns in pedagogical agents [A]. Intelligent tutoring systems, 6th international conference, ITS 2002 proceedings [C]. Berlin: Springer, 2002.81-90.
4Ioannis Hatzilygeroudis,Jim Prentzas. Using a hybrid rule-based approach in developing an intelligent tutoring system with knowledge acquisition and update capabilities [J]. Journal of Expert Systems with Applications, 2004,26(4) :477-492.