1. IEEE Standard for Learning Object Metadata, std 1484.12.1-2002 edition (2002)
2. IEEE standard for learning technology-learning technology systems architecture (LTSA), std 1484.1-2003 edition (2003)
3. Advanced Distributed Systems (ADL) Lab, Sharable Content Object Reference Model (SCORM), http://www.adlnet.org/index.cfm?fuseaction=scormabt
4. Ajami, K.: Specifying and implementing interoperable and reusable learning objects: one step beyond. In: Proc. of Intl. Conf. on Information and Communication Technologies: From Theory to Applications, pp. 111–112 (2004)
5. Baader, F., Calvanese, D., Mc Guinness, D., Nardi, D., Patel-Schneider, P. (eds.): The Description Logic Handbook. Cambridge University Press, Cambridge (2002)