M. Muro, M. Amoretti, F. Zanichelli, and G. Conte. Applied Sciences in Biomedical and Communication Technologies (ISABEL), 2010 3rd International Symposium on, page 1 -5. (November 2010)
J. Bañares, P. Muro-Medrano, and J. Villarroel. Application and Theory of Petri Nets, volume 691 of Lecture Notes in Computer Science, page 32-48. Springer, (1993)