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
Approaches to Adding Persistence to Java January 1, 1996 by Roberto Zicari · Published January 1, 1996 · Last modified February 19, 2014
038.02 The JDO Object Model June 1, 2001 by Roberto Zicari · Published June 1, 2001 · Last modified February 18, 2014