webpage http://www.scopus.com/inward/record.url?eid=2-s2.0-35348837824&partnerID=MN8TOARS http://dx.doi.org/10.1145/1242572.1242809
published in 16th International World Wide Web Conference, WWW2007 Proceedings Proceedings of the 16th international conference on World Wide Web Journal Proceedings of the 16th international conference on World Wide Web Proceedings