T. Ishikawa, P. Klaisubun, M. Honma, and Z. Qian. WI-IATW '06: Proceedings of the 2006 IEEE/WIC/ACM International Conference on Web Intelligence and Intelligent Agent Technology (WI-IAT 2006 Workshops)(WI-IATW'06), page 192--195. Washington, DC, USA, IEEE Computer Society, (2006)
D. Kelly, and N. Belkin. Proceedings of the 27th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval, page 377--384. New York, NY, USA, ACM, (2004)
E. Brown, T. Fisher, and T. Brailsford. HT '07: Proceedings of the 18th conference on Hypertext and hypermedia, page 57--66. New York, NY, USA, ACM, (2007)