1. Bull, S., Vatrapu, R.: Negotiated learner models for today. In: ICCE (2012)
2. Bull, S., Pain, H.: Did I say what I think I said, and do you agree with me?: inspecting and questioning the student model. In: Greer, J. (ed.) AIED 1995, pp. 501–508. AACE, Charlottesville (1995)
3. Fisher, R., Ury, W.: Getting to Yes: Negotiating Agreement without giving in. Penguin books, New York (1983)
4. Lecture Notes in Computer Science;B Lehman,2008
5. Lepper, M.R., et al.: Motivational techniques of expert human tutors: lessons for the design of computer-based tutors. In: Computers as cognitive tools, pp. 75–105 (1993)