Object-Oriented Programming Concepts by Roberto Zicari · Published November 10, 2013 · Updated November 10, 2013 Sun, The Java Tutorial A great tutorial to get acquainted with OOP. LINK
PM3: An Orthogonally Persistent Systems Programming Language January 1, 1999 by Roberto Zicari · Published January 1, 1999 · Last modified February 19, 2014
Contracted Persistent Object Programming November 1, 2005 by Roberto Zicari · Published November 1, 2005 · Last modified July 11, 2014