C. Neuwirth, D. Kaufer, R. Chandhok, and J. Morris. Proceedings of the 1990 ACM conference on Computer-supported cooperative work, page 183--195. New York, NY, USA, ACM, (1990)
C. Liao, F. Guimbreti&\#232;re, and K. Hinckley. UIST '05: Proceedings of the 18th annual ACM symposium on User interface software and technology, page 241--244. New York, NY, USA, ACM, (2005)
S. Bao, G. Xue, X. Wu, Y. Yu, B. Fei, and Z. Su. Proceedings of the 16th International Conference on World Wide Web, page 501--510. New York, NY, USA, ACM, (2007)
R. Yan, A. Natsev, and M. Campbell. MS '07: Workshop on multimedia information retrieval on The many faces of multimedia semantics, page 13--20. New York, NY, USA, ACM Press, (2007)
P. Dmitriev, N. Eiron, M. Fontoura, and E. Shekita. WWW '06: Proceedings of the 15th international conference on World Wide Web, page 811--817. New York, NY, USA, ACM, (2006)
J. Kim, R. Farzan, and P. Brusilovsky. HT '08: Proceedings of the nineteenth ACM conference on Hypertext and hypermedia, page 233--234. New York, NY, USA, ACM, (2008)
J. Kim, R. Farzan, and P. Brusilovsky. BooksOnline '08: Proceeding of the 2008 ACM workshop on Research advances in large digital book repositories, page 25--28. New York, NY, USA, ACM, (2008)
P. Brusilovsky, H. Hsiao, and M. Yudelson. JCDL '08: Proceedings of the 8th ACM/IEEE-CS joint conference on Digital libraries, page 337--340. New York, NY, USA, ACM, (2008)
G. Buscher, A. Dengel, and L. van Elst. Proceedings of the 31st annual international ACM SIGIR conference on Research and development in information retrieval, page 387--394. New York, NY, USA, ACM, (2008)