Robert Clarisó Jordi Cortadella Verification of Concurrent Systems with Parametric Delays Using Octahedra. 1-33 2007 78 Fundam. Inform. 1 http://iospress.metapress.com/openurl.asp?genre=article&issn=0169-2968&volume=78&issue=1&spage=1 db/journals/fuin/fuin78.html#ClarisoC07