Gregor Engels Baris Güldali Christian Soltenborn Heike Wehrheim Assuring Consistency of Business Process Models and Web Services Using Visual Contracts. 17-31 2007 AGTIVE http://dx.doi.org/10.1007/978-3-540-89020-1_2 conf/agtive/2007 db/conf/agtive/agtive2007.html#EngelsGSW07