Eessaar, E., Aaberg, E. Extending UML profiles to model integrity constraints in SQL databases // Proceedings of the 21th [i. e. 21st] European-Japanese Conference on Information Modelling and Knowledge Bases : EJC2011 : Tallinn, Estonia, June 06-10, 2011. Vol. 1. [Tallinn] : Tallinn University of Technology Press, 2011. p. 47-65 : ill. https://www.researchgate.net/publication/260291830_Extending_UML_Profiles_to_Model_Integrity_Constraints_in_SQL_Databases