Go to libraries which have collections of manuscripts, papers, organizational records, ephemera or other unpublished materials relating to the people, organizations and agencies involved in the events. These are often original, one-of-a-kind materials.

The Andruss Library at http://library.bloomu.edu/Archives/SC/SCindex.html has many special collections and is particularly strong in the history of eastern Pennsylvania and Columbia County. Some of the specific subject areas that are part of Special Collections:

• Radical Labor Publications containing over 1000 pamphlets, booklets. brochures, and newsletters by members of communist, socialist, and labor organizations dating from the 1920s to the 1960s. A listing by author and title has been provided for over 900 of these works.
• Art catalog collection of approximately 8,500 items
• Elinor Keefer Collection of all Caldecott and Newbery award winners
• Covered Bridge Collection of books and ephemera about covered bridges
• Automobile Collection consisting primarily of runs of various periodicals and several books
• The Joseph P. Tustin Papers , including the original diaries of Hessian Revolutionary War officer Captain Johann von Ewald.  The diaries date from 1776-1784, and cover his service with the British Army during the war.  They also include many colored pen-and-ink maps drawn by von Ewald, most done while in the field.  See the maps here.
• Here one will discover finding aids to our official records and manuscripts collections/
• Underground Press Collection: Hoover Institution Supplement 1963-1985 (Ref PN 4784. U53 1986)