• American Memory (http://memory.loc.gov) from the Library of Congress  (http://www.loc.gov)
• If you click on Collection Finder  (http://memory.loc.gov/ammem/collections/finder.html), and scroll down to "Time", you can search this digitized collection 20 years, in most cases, at a time.
• NARA  (U.S. National Archives and Records Administration)  (http://www.archives.gov/index.html)
• Presidential Libraries (http://www.archives.gov/presidential_libraries/index.html)

• First Gov  (http://www.firstgov.gov)  Official Website of the U.S. Government

• OAC (Online Archive of California) (http://www.oac.cdlib.org)

• California Heritage Collection (http://sunsite.berkeley.edu/CalHeritage) from the Berkeley Digital Library Sun SITE (http://sunsite.berkeley.edu) which has a vast number of COLLECTIONS (http://sunsite.berkeley.edu/Collections)
• Lessons from teachers using Cal Heritage
• International Studies Academy,San Francisco

The New Deal and Social Welfare: Whose responsibility is it to help those in economic need?
 
• Lincoln High School,San Francisco

1934 S. F. Longshoremen's and General Strikes

Was it Justified to Exclude the Chinese from the U.S. in 1882?
 

• Oakland Unified School District

Why Struggle for Social Change? A case study of the United Farm Workers

California Digital Library (http://www.cdlib.org)

• Online Archive of California (http://www.oac.cdlib.org)

• Search Engines (http://everyschool.org/u/global/tlai/searchengine.html)

• LII (Librarians' Index to the Internet) Search Engine Page (http://lii.org/search/file/searchtools)
• LII  (http://lii.org)

• General Reference Site
• ibiblio -- the Publics' Library (http://www.ibiblio.org/collection)