K. Schoefegger, P. Seitlinger, und T. Ley. Proceedings of the 1st Workshop on Recommender Systems for Technology Enhanced Learning (RecSysTEL 2010), 1, Seite 2829 - 2838. (07.09.2010)
E. Michlmayr, und S. Cayzer. Proceedings of the Workshop on Tagging and Metadata for Social Information Organization, 16th International World Wide Web Conference, (2007)