ODS covers all types of official United Nations documentation, beginning in 1993 and older documents are added to the system on a daily basis. ODS also provides access to the resolutions of the General Assembly, Security Council, Economic and Social Council and the Trusteeship Council from 1946 onwards.

OMIM, Online Mendelian Inheritance in Man is a catalog of human genes and genetic disorders.

An online resource, Opposing Viewpoints in Context, covers today's hottest social issues and includes pro/con viewpoints, reference articles, interactive maps, info-graphics and more. Supports social sciences, sciences, humanities, and current events

Orchestral Music Online is the most recent iteration of David Daniels's classic repertoire reference work used by conductors, orchestras, musicians, and musicologists throughout the world. This new database version is based on the fourth edition of Orchestral Music: A Handbook (2005), and provides greater and easier access to more information on composers and works. Features monthly updates with new composers, new works, additional information, and corrections.