1. Workflow Management Coalition: Workflow management coalition specification-terminology & glossary (WFMC-TC-1011) (1999).
www.wfmc.org
2. Workflow Management Coalition: The workflow reference model (WFMC-TC-1003) (1995).
www.wfmc.org
3. UML (Unified Modeling Language): Superstructure, v2.5.
http://www.omg.org/
4. Yawl (Yet Another Workflow Language).
http://www.yawlfoundation.org/
5. Laurent Audibert: Cours UML.
https://laurent-audibert.developpez.com/Cours-UML/?page=diagramme-activites