Hajo A. Reijers R. S. Mans Robert A. van der Toorn Improved model management with aggregated business process models. 221-243 2009 68 Data Knowl. Eng. 2 http://dx.doi.org/10.1016/j.datak.2008.09.004 db/journals/dke/dke68.html#ReijersMT09