1. OMG, Unified Modeling Language version 2.5.1, OMG Document Number: formal/17-12-05, 2017, https://www.omg.org/spec/UML/2.5.1/.
2. Circumscription—A form of non-monotonic reasoning;McCarthy;Artificial Intelligence,1980
3. S. Cranefield, M. Purvis, UML as an ontology modeling language, in: Proceedings of the Workshop on Intelligent Information Integration, Stockholm, Sweden, 1999.
4. Object-oriented Analysis and Design with Applications;Booch,1994
5. Object-oriented Modeling and Design;Rumbaugh,1991