Richard Torbjørn Sanders Humberto Nicolás Castejón Frank Alexander Kraemer Rolv Bræk Using UML 2.0 Collaborations for Compositional Service Specification. 460-475 2005 conf/uml/2005 MoDELS http://dx.doi.org/10.1007/11557432_35 db/conf/uml/models2005.html#SandersMKB05