1. Anderson, J. R.: 1988, ?The expert Module?. In: M. C. Polson and J. J. Richardson (eds.):Foundations of Intelligent Tutoring systems. Hillsdale, NJ: Lawrence Erlbaum, pp. 21?53.
2. Boy, G.: 1991, ?On-line User Model Acquisition in Hypertext Documentation?. In:Proceedings of the IJCAI Workshop W4: Agent Modelling for Intelligent Interaction, Sydney, Australia, pp. 34?42.
3. Boyle, C. and A. Encarnacion: 1991, ?A User Model Based Hypertext Documentation System?. In:Proceedings of the IJCAI Workshop, pp. 43?65 (The system is also described in: C. Boyle and A. O. Encarnacion: 1994, ?Meta-Doc: An Adaptive Hypertext Reading System?. In:User Modeling and User-Adapted Interaction, this issue.)
4. Brownston, L., et al.: 1985,Programming Expert Systems in Ops5. Reading, Massachusetts: Addison-Wesley.
5. Chin, D.: 1986, ?User Modelling in UC: the Unix Consultant?. InProceedings of the CHI-86 Conference, Boston.