@InCollection{Clark:2002:inOCL, author = "Tony Clark and Andy Evans and Stuart Kent", title = "A Meta-model Facility for a Family of {UML} Constraint Languages", booktitle = "Object Modeling with the OCL: The Rationale behind the Object Constraint Language", publisher = "Springer", year = "2002", editor = "Tony Clark and Jos Warmer", pages = "4--20", isbn = "3-540-43169-1", }