Vahid Rafe Adel Torkaman Rahmani Formal Analysis of Workflows Using UML 2.0 Activities and Graph Transformation Systems. 305-318 2008 ICTAC http://dx.doi.org/10.1007/978-3-540-85762-4_21 conf/ictac/2008 db/conf/ictac/ictac2008.html#RafeR08