H. Bast, A. Chitea, F. Suchanek, and I. Weber. Proceedings of the 30th annual international ACM SIGIR conference on Research and development in information retrieval, page 671--678. ACM, (2007)
F. Moser, R. Ge, and M. Ester. KDD '07: Proceedings of the 13th ACM SIGKDD international conference on Knowledge discovery and data mining, page 510--519. New York, NY, USA, ACM, (2007)