Polymorphism Courses
Pluralsight Functional Program Design in Scala (Scala 2 version)
École Polytechnique Fédérale de Lausanne via Coursera Object-Oriented Programming Concepts
LearnQuest via Coursera Working with Classes and Interfaces in Java
Pluralsight Capturing Logic with Custom Functions in PostgreSQL
Pluralsight Creating Object-oriented TypeScript Code
Pluralsight C++ from Beginner to Expert
Skillshare Java from Beginner to Expert
Skillshare Advanced Python
YouTube Object Oriented Programming in C++ (Indonesian Version)
Udemy