To identify non-U.S. papers from a particular time and place, it is often sufficient to consult one of these general guides:
Concrete information about a newspaper's ownership, circulation, and readership can be elusive. First, search for a book or article on the paper in which you are interested. Otherwise, consult a general directory of newspapers and periodicals for the period of interest (see above).
If Princeton does not hold the newspaper you need, you may be able to obtain microfilm of the paper through Interlibrary Loan. In particular, many newspapers are available on microfilm from the Center for Research Libraries, an organization of which Princeton is a member. CRL collects not only mainstream U.S. papers, but also U.S. ethnic papers (searchable by ethnic group in their online catalog) and foreign newspapers.
The Library of Congress, state archives and libraries, local historical societies, and some large public libraries have substantial collections of local U.S. newspapers, in print and in microfilm, often including titles available nowhere else. The New York Public Library also has a substantial collection of newspapers. Much of this material is not available through Interlibrary Loan, so you must travel to the archive or library to see the paper you need. To find out where you might find a specific newspaper, check Worldcat or one of the guides listed above.
A useful (but dated) guide to several important newspaper collections is:
Untapped sources: America's newspaper archives and histories. Prepared for the American Society of Newspaper Editors' Newspaper History Task Force by the Gannett Foundation Media Center at Columbia University in the City of New York; written by Jon Vanden Heuvel; edited by Craig LaMay and Martha FitzSimon. [New York: Columbia University; 1991.]
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