@InProceedings{Dong:2001:WRKUML,
  author =       "Zhijiang Dong and Xudong He",
  title =        "Integrating {UML} Statecharts and Collaboration Diagrams
                  Using Hierarchical Predicate Transition Nets",
  pages =        "99--112",
  booktitle =    "Practical {UML}-Based Rigorous Development Methods -
                  Countering or Integrating the e{X}tremists. Workshop of
                  the {pUML}-Group held together with the UML 2001 October
                  1st, 2001 in Toronto, Canada",
  editor =       "Andy Evans and Robert France and Ana Moreira and Bernhard
                  Rumpe",
  publisher =    "German Informatics Society",
  series =       "LNI",
  volume =       "P-7",
  year =         "2001",
}