Eric Badouel Jules Chenou Goulven Guillou An Axiomatization of the Token Game Based on Petri Algebras. 187-215 2007 77 Fundam. Inform. 3 http://iospress.metapress.com/openurl.asp?genre=article&issn=0169-2968&volume=77&issue=3&spage=187 db/journals/fuin/fuin77.html#BadouelCG07