@incollection{UBHD-68468076,
  author={Kotb, Yehia and Baumgart, André},
  title={An extended Petri net for modeling workflow with critical sections},
  year={2005},
  pages={134-141},
  language={eng},
  isbn={0769524303},
  note={Gesehen am 16.12.2019},
  booktitle={IEEE International Conference on e-Business Engineering, 2005},
  doi={10.1109/ICEBE.2005.27},
}
@incollection{UBHD-68468077,
  author={Kotb, Yehia and Badreddin, Essameddin},
  title={Synchronization among activities in a workflow using extended workflow Petri nets},
  year={2005},
  pages={548-551},
  language={eng},
  isbn={0769523846},
  note={Gesehen am 16.12.2019},
  booktitle={Seventh IEEE International Conference on E-Commerce Technology workshops 2005},
  doi={10.1109/ICECT.2005.89},
}