- https://www.tutorialspoint.com/cplusplus/index.htm
- https://www.programiz.com/cpp-programming/operator-overloading
- https://www.programiz.com/cpp-programming/templates
- https://www.tutorialspoint.com/pure-virtual-functions-and-abstract-classes-in-cplusplus
- https://www.techiedelight.com/difference-between-static-dynamic-binding-cpp/