Y. Song, L. Zhang, and C. Giles. CIKM '08: Proceeding of the 17th ACM conference on Information and knowledge management, page 93--102. New York, NY, USA, ACM, (2008)
H. Lee, A. Borodin, and L. Goldsmith. HT '08: Proceedings of the nineteenth ACM conference on Hypertext and hypermedia, page 139--148. New York, NY, USA, ACM, (2008)