C. de Souza, S. Quirk, E. Trainer, и D. Redmiles. Proceedings of the 2007 international ACM conference on Supporting group work, стр. 147--156. New York, NY, USA, ACM, (2007)
J. Howse. Proceedings of the 16th International Conference on Conceptual Structures (ICCS 2008), том 5113 из Lecture Notes in Computer Science, стр. 1-20. Springer, (2008)