H. Wu, M. Zubair, and K. Maly. HYPERTEXT '06: Proceedings of the seventeenth conference on Hypertext and hypermedia, page 111--114. New York, NY, USA, ACM, (2006)
M. Choudhury, H. Sundaram, A. John, and D. Seligmann. WWW '09: Proceedings of the 18th international conference on World wide web, page 331--340. New York, NY, USA, ACM, (2009)