D. Gruhl, R. Guha, R. Kumar, J. Novak, and A. Tomkins. KDD '05: Proceeding of the eleventh ACM SIGKDD international conference on Knowledge discovery in data mining, page 78--87. New York, NY, USA, ACM Press, (2005)
C. de Souza, S. Quirk, E. Trainer, and D. Redmiles. Proceedings of the 2007 international ACM conference on Supporting group work, page 147--156. New York, NY, USA, ACM, (2007)