The interoperability of learning object repositories and services: standards, implementations and lessons learned.
M. Hatala, G. Richards, T. Eap, J. Willms. The Interoperability of Learning Object Repositories and Services: Standards, Implementations and Lessons Learned, In Proc. World Wide Web Conference, 13 ed. ACM Press, 2004, ISBN: 158113-844-X.
2004