Object-Oriented Databases versus Object-Relational Databases - Gives a rough definition of relational, object-oriented and object-relational databases and compares these paradigms using criteria such as simplicity of use, scalability and maturity. - http://www.ca.com/products/jasmine/analyst/idc/14821Eat.htm
The Object-Oriented Database System Manifesto - Defines the main features and characteristics that a system must have to qualify as an object-oriented database. - http://www.cs.cmu.edu/People/clamen/OODBMS/Manifesto/htManifesto/Manifesto.html
Object-Oriented Database Management Systems - A collection of links, background, research, requirements, books, newsgroups, and organizations. Includes pointers to the three manifestos. - http://www.cs.cmu.edu/People/clamen/OODBMS/
Object Data Management Group (ODMG) - Industry association for a common OO data standard. Extracts of ODMG 3.0 as well as some explaining articles are online. Note: Standard is partially superceded by JDO. - http://www.odmg.org/
ODBMS Articles and Products - Articles on object-oriented database systems architecture and technology, product comparison and selection as well as a small FAQ. - http://www.service-architecture.com/object-oriented-databases
Whatever Happened to Object-Oriented Databases? - Comparison of state and future prospect of object-oriented and relational databases. [PDF file with IEEE Computer version available from same site.] - http://www.leavcom.com/db_08_00.htm
Cetus - Link collection with FAQs, newsgroups, books, and conferences. - http://www.cetus-links.org/oo_data_bases.html