ConceptBase by Roberto Zicari · Published January 1, 2008 · Updated February 16, 2014 Tilburg University ConceptBase is a multi-user deductive and object-oriented database system for meta modeling and method engineering (FreeBSD-style license) LINK
The ZooDB Object Database January 23, 2015 by Roberto Zicari · Published January 23, 2015 · Last modified May 17, 2015
Perst. Open Source, Object-Oriented Embedded Database January 1, 2009 by Roberto Zicari · Published January 1, 2009 · Last modified March 12, 2019
The Open Source Database Benchmark January 1, 2005 by Roberto Zicari · Published January 1, 2005 · Last modified February 16, 2014