- Encarta Encyclopedia Article Center: Contains 5,000 searchable articles. Some content is free, but premium content requires a subscription.
- Encyclopedia Britannica: (Subscription Required) Includes over 75,000 articles, the World Data Analyst Online, the Merriam-Webster's Dictionary of Quotations, audio-visual materials, and more.
- HighBeam Encyclopedia: Free access to 57,000 articles from the Columbia Encyclopedia, Sixth Edition.
- Wikipedia: Contains over a million entries, edited by users. Constantly updated so may be more useful on current events than other sources.