Book Source Accessed Electronically
Alabama Virtual Library (AVL) Database: Nonfiction collection
AVL Student Research Center (choose to search only "books" as material type)
Google Books (look for "limited preview" or "full view")

Periodicals (magazines) & Journals
AVL Student Research Center (choose to search only periodicals)
AVL SIRS
AVL EBSCO

Primary Source Documents
American Memory Collection (Library of Congress)
EDSITEment Social Studies
History, It's Happening!
Digital History

Website Source
Use Reference Desk
Use Goodsearch and put your search term phrase in "quotation marks"
Use Yahoo's Directory Search (U.S. History/People)
Use Yahoo's Directory Search (U.S. History)
Use America's Story (Library.gov)
Use Google's "advanced search" features to limit search to only .org; .net; .edu; or .gov sites.