Simona Bernardi Andrea Bobbio Susanna Donatelli Petri Nets and Dependability. 125-179 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3098&spage=125 2003 conf/ac/2003pn Lectures on Concurrency and Petri Nets db/conf/ac/acpn2003.html#BernardiBD03