1. Baghaei, N., Mitrovic, A., Irwin, W.: A Constraint-Based Tutor for Learning Object-Oriented Analysis and Design using UML. In: Looi, C., Jonassen, D., Ikeda, M. (eds.) ICCE 2005, pp. 11–18 (2005)
2. Baghaei, N., Mitrovic, A., Irwin, W.: Problem-Solving Support in a Constraint-based Tutor for UML Class Diagrams. Technology, Instruction, Cognition and Learning Journal 4(1-2) (in print, 2006)
3. Constantino-Gonzalez, M., Suthers, D.: Coaching Collaboration in a Computer-Mediated Learning Environment. In: CSCL 2002, NJ, USA, pp. 583–584 (2002)
4. Dillenbourg, P.: What do you mean by Collaborative Learning. In: Dillenbourg, P. (ed.) Collaborative Learning: Cognitive and Computational Approaches, pp. 1–19. Elsevier Science, Amsterdam (1999)
5. Fowler, M.: UML Distilled: a Brief Guide to the Standard Object Modelling Language, 3rd edn. Addison-Wesley, Reading (2004)