Reference Materials :

http://www.britannica.com             Britannica Encyclopedia.
Complete text of the encyclopedia, plus thousands of photos, graphics and illustrations.

http://www.loc.gov/    Library of Congress.  
Search its catalogs.  Advanced searches. 

http://www.libraryspot.com   Library Spot.
Libraries, Reference Desks, Reading Selections, etc.

http://refdesk.com                Reference Desk.   

Source of facts.  Reference Resources.

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