1. Reusable learning objects: a survey of LOM-based repositories;Neven,2002
2. Towards interoperable learning object repositories: the Ariadne experience;Najjar,2003
3. The interoperability of learning object repositories and services: standards, implementations and lessons learned;Hatala,2004
4. Bridging repositories to form the MACE experience;Wolpers;N. Rev. Inform. Netw.,2009
5. Interoperability for searching learning object repositories: the ProLearn Query Language;Ternier;D-Lib Magazine,2008