Jan Mendling Boudewijn F. van Dongen Wil M. P. van der Aalst Getting Rid of the OR-Join in Business Process Models. 3-14 2007 conf/edoc/2007 EDOC http://doi.ieeecomputersociety.org/10.1109/EDOC.2007.30 db/conf/edoc/edoc2007.html#MendlingDA07