1. Allen, R. B. (1983). Cognitive factors in the use of menus and trees: An experiment. IEEE Journal on Selected Areas in Communications, SAC-1(2), 333-336.
2. Breuker, J. & de Greef, P. (1985). Information processing system and tmhtng @coaching in HELPsystems (Deliverable 12.1 ESPRIT Project P280). Amsterdam: Department of Social Science Informatics, University of Amsterdam, Herengracht196, 1016 BS Amsterdam.
3. Brockmann, R. J. (1986). Writing better computer user documentation: From paper to online New York: Wiley.
4. Card, S. K. (1982). User perceptual mechanisms in the search of computer command menus. Proceedings of the CHI '82 Conference on Human Factors in Computer Science, 190-196. New York: ACM.
5. Duffy, T. M., Mehlenbacher, B. & Palmer, J. (1989). The evaluation of online help systems: A conceptual model. In E. Barrett (Ed.), 77z.e s w e @ of text: Hypntext, hypmncdur, and the social construction of infomtwn (pp. 362-387). Cambridge, MA: MIT Press.