F. Abel, N. Henze, и D. Krause. Proceedings of the 17th ACM Conference on Information and Knowledge Management, CIKM 2008, Napa Valley, California, USA, October 26-30, 2008, стр. 1429-1430. ACM, (2008)
R. Wetzker, W. Umbrath, и A. Said. Proceedings of the WSDM '09 Workshop on Exploiting Semantic Annotations in Information Retrieval, стр. 25--29. New York, NY, USA, ACM, (2009)