1. Ackoff, R. L.(1968). Fundamentals of Operations Research. Chapters 1–3. John Wiley & Sons. NY.
2. Angelides, M.C. & Doukidis, G.I. (1990). Is there a place in OR for Intelligent Tutoring Systems?. Journal of Operations Research Society. 41(6), 491–503
3. Chiang, L & García, D.M (1994) Problem Classifier System, Proceedings of International Conference Informatics'94, Havana, Cuba.
4. Churchman, C. West, Ackoff, R. L., Arnoff, E. L. (1957) Introduction to Operations Research. Wiley. NY.
5. Clancey, W.(1982). Tutoring rules for guiding a case method dialogue, in Intelligent Tutoring Systems edited by Sleeman, D. & Brown J.S. Englewood Cliffs, N J, Prentice Hall.