Also for those who visit the Library of Congress in Washingtion, DC, one can access numerous databases for research. These are subscription databases for which the library pays, ones that are rather expensive, but are available free of charge at the library. One database that I've found particularly useful is the Chadwyck-Healey African American Biographical Database.

The database is comprised of a broad spectrum of publications, many which are African American and are out of print. One can search by name, occupation and location. You can also do a keyword and full text search.

The beauty of using this database is that you can not only locate obscure sources, but also print the entries free of charge.

Check the link below for more information. At the bottom of the web page is a link to sign up for a free trial.