Inheritance Courses
Pluralsight Object-Oriented Programming Fundamentals in C#
Pluralsight Object-Oriented Programming In PHP - The Right Way
Skillshare Templating with Twig Course (How To)
Treehouse Inheritance in Java Course (How To)
Treehouse Extending Object-Oriented PHP Course (How To)
Treehouse Object-Oriented Python Course (How To)
Treehouse Object Oriented JavaScript
Net Ninja via YouTube Object Oriented PHP Tutorial
YouTube Object-oriented programming
Higher School of Economics via Coursera