P. Victor, C. Cornelis, A. Teredesai, and M. De Cock. SAC '08: Proceedings of the 2008 ACM symposium on Applied computing, page 2014--2018. New York, NY, USA, ACM, (2008)
G. Groh, and C. Ehmig. GROUP '07: Proceedings of the 2007 international ACM conference on Supporting group work, page 127--136. New York, NY, USA, ACM, (2007)
Y. Huang, N. Contractor, and Y. Yao. dg.o '08: Proceedings of the 2008 international conference on Digital government research, page 27--33. Digital Government Society of North America, (2008)
I. Konstas, V. Stathopoulos, and J. Jose. Proceedings of the 32nd international ACM SIGIR conference on Research and development in information retrieval, page 195--202. New York, NY, USA, ACM, (2009)
G. Groh, S. Birnkammerer, and V. Köllhofer. Recommender Systems for the Social Web, volume 32 of Intelligent Systems Reference Library, chapter 1, Springer Berlin Heidelberg, Berlin, Heidelberg, (2012)