U.S. Library of Congress American Memory provides access historic maps, photos, documents, audio and video. The collection can be keyword searched or browsed by topic, time period, or media types.
"Primary sources are original records created at the time historical events occurred or well after events in the form of memoirs and oral histories. Primary sources may include letters, manuscripts, diaries, journals, newspapers, speeches, interviews, memoirs, documents produced by government agencies such as Congress or the Office of the President, photographs, audio recordings, moving pictures or video recordings, research data, and objects or artifacts such as works of art or ancient roads, buildings, tools, and weapons. These sources serve as the raw material to interpret the past, and when they are used along with previous interpretations by historians, they provide the resources necessary for historical research." (Source: Using Primary Sources on the Web, a website created by the History Section of the American Library Association's Reference and User Services.)
The primary sources held at NMSU will be found in Archives and Special Collections, housed in Branson Library: location and hours. The Rio Grande Historical Collections, Hobson-Huntsinger University Archives, and Special Collections serve as a repository for non-current NMSU records and for manuscripts, personal papers and non-circulating material documenting the cultural heritage and history of New Mexico and the Southwest. In the NMSU Library catalog, using terms such as Personal Narrative, Diaries, Correspondence, or Sources as keywords combined with your area of research can retrieve primary source holdings. For example, in a Combined Keywords search, using Las Cruces as a Keyword, and Sources as a Subject, primary sources such as postcards, letters and other papers are located.
You may also search the Rocky Mountain Online Archive, a source of information about archival collections in Colorado, New Mexico and Wyoming.
American Periodical Series Online, 1740-1900 Contains digitized images of the pages of American journals that originated in 1741, when Benjamin Franklin's General Magazine was launched through 1900.
American State Papers, 1789-1838 The American State Papers provides primary source material on many aspects of early American history.
Archive of Americana The Archive of Americana includes: American State Papers, 1789-1838; the U.S. Congressional Serial Set, 1817-1980; and the Serial Set Maps.
Cornell University American History & Culture. Students of American history will find a rich selection of manuscripts from the colonial and revolutionary war periods to the present.
Digital History. More than 600 annotated documents dealing with American politics, diplomacy, and social history.
Early Americas Digital Archive. Original writings from about the Americas ~1492-1820.
History Matters - Many Pasts. Has primary documents in text, image, and audio about the experiences of ordinary Americans throughout U.S. history. All are screened by professional historians annotated as to their larger historical significance and context.
The Library of Congress Primary Documents in American History. From 1763-1877.
The National Archives America's Historical Documents.
Our Documents. Sponsored by the National Archives and Records Administration and National History Day, this features one hundred "milestone documents of American history."
Repositories of Primary Sources gateway.
Center for Retrospective Digitization. At the Göttingen State Library in Germany. Offers some 5 million digital pages from historic books, maps, and periodicals, primarily German-language.
Gallica. The Digital Library of the National Library of France - akin to Library of Congress's American Memory.
Internet Library of Early Journals. A digitization of substantial runs of 18th and 19th century U.K. journals, together with their associated bibliographic data.
The National Archives of the United Kingdom. Containing 900 years of history with records ranging from parchment and paper scrolls through to digital files.
Repositories of Primary Sources gateway.
Euro Docs is a directory of primary documents in Western European history compiled by Richard Hacken, librarian at Brigham Young University.
Historians usually use Chicago style for citations.
Here is a sample paper, with notes and bibliography.
"Making of America (MOA) is a digital library of primary sources in American social history primarily from the antebellum period through reconstruction. The collection is particularly strong in the subject areas of education, psychology, American history, sociology, religion, and science and technology" (University of Michigan).