@InProceedings{Saksena:1999:UML98,
  author =       "Monika Saksena and Maria Larrondo-Petrie and Robert B.
                  France and Matthew Evett",
  title =        "Extending Aggregation Constructs in {UML}",
  pages =        "434--441",
  booktitle =    "The Unified Modeling Language, UML'98 - Beyond the
                  Notation. First International Workshop, Mulhouse, France,
                  June 1998, Selected Papers",
  editor =       "Jean B{\'e}zivin and Pierre-Alain Muller",
  publisher =    "Springer",
  series =       "LNCS",
  volume =       "1618",
  year =         "1999",
}