[spec UML](https://www.omg.org/spec/UML) v2.5.1 Декабрь 2017 г.

### UseCase
- [UseCase diagram](https://flexberry.github.io/ru/fd_use-case-diagram.html)
- [lucidchart](https://www.lucidchart.com/pages/uml-use-case-diagram)
- [habr](https://habr.com/ru/articles/913318/)

### Use-case 3.0
- [Use-case 3.0: краткое руководство habr](https://habr.com/ru/articles/873952/)
- [ailev](https://ailev.livejournal.com/1745161.html)