1. D.C. Engelbart, W.K. English, ?A research center for augmenting human intellect,? in Proceedings of the AFIPS Fall Joint Computer Conference, The Thompson Book Company, Washington, D.C., 1968, pp. 395?410.
2. M.J. Stefik, ?The next knowledge medium,?AI Magazine, vol. 7, pp. 34?46, 1986.
3. G. Fischer, ?Communications requirements for cooperative problem solving systems,?The International Journal of Information Systems (Special Issue on Knowledge Engineering), vol. 15, pp. 21?36, 1990.
4. R.R. Burton, J.S. Brown, G. Fischer, ?Analysis of skiing as a success model of instruction: Manipulating the learning environment to enhance skill acquisition,? in Everyday Cognition: Its Development in Social Context, edited by B. Rogoff, J. Lave, Harvard University Press: Cambridge, MA?London, pp. 139?150, 1984.
5. T.W. Malone, ?How do people organize their desks? Implications for the design of office information systems,?ACM Transactions on Office Information Systems, vol. 1, pp. 99?112, 1983.