J. Hidders, M. Dumas, W. van der Aalst, A. ter Hofstede, and J. Verelst. Proceedings of the 2005 Australasian Symposium on Theory of Computing - Volume 41, page 3--11. Darlinghurst, Australia, Australia, Australian Computer Society, Inc., (2005)
A. Negri, A. Poggi, M. Tomaiuolo, and P. Turci. Proceedings of the fifth international joint conference on Autonomous
agents and multiagent systems, page 907--914. New York, NY, USA, ACM, (2006)