Merge pull request #33 from pythonlover02/next

add missing note on the references

Author: pythonlover02

README.md

@@ -238,6 +238,7 @@ Documentation used:
 - [NVIDIA 470 Drivers - Documentation](https://download.nvidia.com/XFree86/Linux-x86_64/470.256.02/README/openglenvvariables.html)
 - [NVIDIA 390 Drivers - Documentation](https://download.nvidia.com/XFree86/Linux-x86_64/390.157/README/openglenvvariables.html)
 - [Linux Kernel - Subsystem Documentation](https://docs.kernel.org/subsystem-apis.html)
+- Additionally, sometimes i had to read code from Open Source projects to check how some options work.
 
 ## Contributing: