1. SCORM: http://www.adlnet.gov/scorm/index.cfm
2. Wolz, U., McKeown, K.R., Kaiser, G.E.: Automated Tutoring in Interactive Environments: A Task-Centered Approach. In: Intelligent Instruction by Computer, Theory and Practice, Taylor & Francis, New York (1992)
3. Lecture Notes in Computer Science;E. Leung,2003
4. Lecture Notes in Computer Science;E. Leung,2005
5. WebCT: http://www.webct.com/