For more information, you can refer to the following links:
- What is the Python Global Interpreter Lock (GIL)? (realpython.com/python-gil/), Abhinav Ajitsaria
- The Python GIL Visualized (dabeaz.blogspot.com/2010/01/python-gil-visualized), Dave Beazley
- Copy Operations in Python (pythontic.com/modules/copy/introduction)
- It isn't Easy to Remove the GIL (www.artima.com/weblogs/viewpost.jsp?thread=214235), Guido Van Rossum
- Parallel Programming with Python, by Jan Palach, Packt Publishing Ltd, 2014
- Learning Concurrency in Python: Build highly efficient, robust, and concurrent applications, Elliot Forbes (2017)