J. Herlocker, J. Konstan, and J. Riedl. CSCW '00: Proceedings of the 2000 ACM conference on Computer supported cooperative work, page 241--250. New York, NY, USA, ACM Press, (2000)
M. Coyle, and B. Smyth. IUI '07: Proceedings of the 12th international conference on Intelligent user interfaces, page 282--285. New York, NY, USA, ACM Press, (2007)