A good way to learn more is to search for books about topics you're interested in e.g.; sqlite, zeromq, google testing libraries, opengl...

1. https://www.amazon.co.uk/Design-Patterns-Object-Oriented-Add...

2. https://www.oreilly.com/library/view/using-sqlite/9781449394...

3. https://www.glprogramming.com/red/

4. https://gameprogrammingpatterns.com/

5. https://zguide.zeromq.org/