Elzbieta Krepska Nicola Bonzanni K. Anton Feenstra Wan Fokkink Thilo Kielmann Henri E. Bal Jaap Heringa Design Issues for Qualitative Modelling of Biological Cells with Petri Nets. 48-62 2008 FMSB http://dx.doi.org/10.1007/978-3-540-68413-8_4 conf/fmsb/2008 db/conf/fmsb/fmsb2008.html#KrepskaBFFKBH08