Wetzker, Robert ; Umbrath, Winfried ; Said, Alan: A hybrid approach to item recommendation in folksonomies. In: Proceedings of the WSDM '09 Workshop on Exploiting Semantic Annotations in Information Retrieval. New York, NY, USA : ACM, 2009 (ESAIR '09). - ISBN 978-1-60558-430-0, S. 25--29