@InProceedings{BaarHaehnle00,
  author        = {Thomas Baar and Reiner H\"{a}hnle},
  title         = {An Integrated Metamodel for {OCL} Types},
  editor        = {R. France},
  year          = {2000},                 
  booktitle =    "OOPSLA 2000 Workshop Refactoring the UML:  In Search of the Core, Minneapolis, Minnesota, USA",
  month         = oct       
}