L. Silva, и L. Jayaratne. Applications of Digital Information and Web Technologies, 2009. ICADIWT '09. Second International Conference on the, стр. 446-451. (августа 2009)
A. Plangprasopchok, и K. Lerman. WWW '09: Proceedings of the 18th international conference on World wide web, стр. 781--790. New York, NY, USA, ACM, (2009)