@InProceedings{Schuerr:1998:FDUPC,
  author =       "Andy Sch{\"u}rr and Andreas Winter",
  title =        "Formal Definition of {UML}'s Package Concept",
  pages =        "144--159",
  booktitle =    "The Unified Modeling Language -- Technical Aspects and
                  Applications",
  editor =       "Martin Schader and Axel Korthaus",
  publisher =    "Physica-Verlag, Heidelberg",
  year =         "1998",
}