R. Jones, R. Kumar, B. Pang, und A. Tomkins. CIKM '07: Proceedings of the sixteenth ACM conference on Conference on information and knowledge management, Seite 909--914. New York, NY, USA, ACM, (2007)
M. Hildebrand, J. van Ossenbruggen, und L. Hardman. International Semantic Web Conference, Volume 4273 von Lecture Notes in Computer Science, Seite 272-285. Springer, (2006)