Online reference resources include online dictionaries, encyclopedias, atlases, almanacs. These resources are helpful for reseach when you want to find information about topics, locate facts, and answer questions.
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Quickly check a fact, or find out key information about a concept, person, or term. The collection contains dictionaries, language reference, and subject reference works published by Oxford University Press.
The Columbia Gazetteer of North America by 
Concise Princeton Encyclopedia of American Political History by 
The Oxford Handbook of the American Presidency by