There are many volumes of primary source material in the Middle School libraries. Try the following strategies to locate the ones you need.
Issues & Controversies in American History
Look for "Primary Sources" on the left navigation menu within your topic.
This subscription database contains primary source documents as well as secondary source articles and analysis.
Research in Context, US History in Context, World in History
These subscription databases contain primary source documents as well as secondary source articles from reference books, periodicals, and elsewhere.
Annals of American History by Encyclopedia Britannica - america.eb.com
American Memory - http://memory.loc.gov/ammem/amhome.html
From the Library of Congress, this ever-expanding collection covers all periods of U.S. history. Note that the "documents" may be images as well as text.
Annotated links to specialized collections within American Memory are available from ipl.org. [curriculum connections]
National Archives - http://www.archives.gov/
National Archives' search engine: http://research.archives.gov/search
ipl.org's annotated lists of selected National Archives collections
Core Documents of U.S. Democracy - http://www.gpo.gov/libraries/core_docs.htm
Supreme Court decisions, bills, executive orders & proclamations, U.S. code, and famous historical documents from the Articles of Confederation forward
World War I Document Archive - http://www.lib.byu.edu/~rdh/wwi/
Assembled by volunteers from the World War I Military History List (WWI-L) online discussion group; hosted by Brigham Young University.
see also: http://www.loc.gov/rr/program/bib/wwi/wwi.html
World War II Resources - http://www.ibiblio.org/pha/
Over 10,000 pages of text reproduced here.
See also: Historic Government Publications from World War II from SMU
New Deal Document Library - http://newdeal.feri.org/texts/
Large, categorized collection of primary source texts, photos, and cartoons.