Walter Vogler Ben Kangsah Improved Decomposition of Signal Transition Graphs. 161-197 2007 78 Fundam. Inform. 1 http://iospress.metapress.com/openurl.asp?genre=article&issn=0169-2968&volume=78&issue=1&spage=161 db/journals/fuin/fuin78.html#VoglerK07