1. Object Management Group: Unified Modeling Language: Superstructure Version 2.2 (09-02-02) (2009), http://www.omg.org/spec/UML/2.2/Superstructure/PDF/
2. International Organization for Standardization (ISO): ISO 5807:1985 Information processing – Documentation symbols and conventions for data, program and system flowcharts, program network charts and system resources charts (1985)
3. Koch, N., Kraus, A., Cacharo, C., Meliá, S.: Integration of business processes in Web application models. Journal of Web Engineering 3(1), 22–49 (2004)
4. Eshuis, H.: Semantics and Verification of UML Activity Diagrams for Workflow Modelling. PhD thesis, Univ. of Twente (2002)
5. Harel, D., Rumpe, B.: Meaningful Modeling: What’s the Semantics of “Semantics“? Computer 37(10), 64–72 (2004)