M. Dowman, V. Tablan, H. Cunningham, and B. Popov. Proceedings of the 14th International World Wide Web Conference, Chiba, Japan, (2005)http://gate.ac.uk/sale/www05/web-assisted-annotation.pdf.
J. Tang, and P. Lewis. CIVR '08: Proceedings of the 2008 international conference on Content-based image and video retrieval, page 105--112. New York, NY, USA, ACM, (2008)