Informix Corporation
Designs, develops, manufactures, markets, and supports database management systems and object-oriented application development tools for delivering information to desktop platforms. (Nasdaq: IFMX).

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 Note: Standard is partially superceded by JDO.

Object-Oriented Database Management Systems
A collection of links, background, research, requirements, books, newsgroups, and organizations. Includes pointers to the three manifestos.

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.

ODBMS Articles and Products
Articles on object-oriented database systems architecture and technology, product comparison and selection as well as a small FAQ.

The Object-Oriented Database System Manifesto
Defines the main features and characteristics that a system must have to qualify as an object-oriented database.

Ultima-S: Problems and Decisions
Advantages of a client-server O(R)DBMS versus a mainframe database are shown.

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.]