Wessel Kraaij Arjen P. de Vries Charles L. A. Clarke Norbert Fuhr Noriko Kando SIGIR 2007: Proceedings of the 30th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval, Amsterdam, The Netherlands, July 23-27, 2007 SIGIR ACM 978-1-59593-597-7 2007 db/conf/sigir/sigir2007.html