Back then OOP was still the new kid on the block, so the other books that helped me get into OOP where
- The Xerox PARC Smalltalk books, http://stephane.ducasse.free.fr/FreeBooks/
- "Eiffel: The Language", Bertrand Meyer
- "An Object-Oriented Environment: Principles and Application", Bertrand Meyer
- "Designing Object Oriented C++ Applications Using The Booch Method"
- "Project Oberon" and "Algorithms and Data Structures, Oberon version", http://www.inf.ethz.ch/personal/wirth/
- "Object-Oriented Programming in Oberon-2.", http://ssw.jku.at/Research/Books/
- "Component Software: Beyond Object-Oriented Programming", first edition uses Component Pascal
There was hardly any Object Pascal representative book, so those books were what made the grasp OO concepts across what were then new languages, more than the specific way of doing OO.