Claudine Chaouiya Elisabeth Remy Paul Ruet Denis Thieffry Qualitative Modelling of Genetic Networks: From Logical Regulatory Graphs to Standard Petri Nets. 137-156 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3099&spage=137 2004 conf/apn/2004 ICATPN db/conf/apn/icatpn2004.html#ChaouiyaRRT04