Oliver Kopp Katharina Görlach Frank Leymann Extending choreography spheres to improve simulations. 696-699 2010 iiWAS https://doi.org/10.1145/1967486.1967598 https://www.wikidata.org/entity/Q59898162 conf/iiwas/2010 db/conf/iiwas/iiwas2010.html#KoppGL10