olemus
UML: üldistuse üks tähistusviise
= a type of generalization notation in UML

https://www.site.uottawa.ca/~tcl/gradtheses/mnojoumian/ThesisFiles/FinalSpec/UML/7.3.20.html

https://astahblog.com/2014/04/22/linestyle_one/

https://www.omg.org/spec/UML/2.1.2/Infrastructure/PDF/