There is bound to be something in at least one of these databases that will help you locate some pertinent primary documents for your paper.
Atlanta Constitution (1868-1984)
Atlanta Daily World (1931-2003)
The Chicago Defender (1909-1975)
Chicago Tribune (1847-1993)
Christian Science Monitor (1908-2003)
Detroit Free Press (1831-1999)
Los Angeles Sentinel (1934-2005)
Los Angeles Times (1881-1992)
The Michigan Chronicle (1939-2010)
The Nashville Tennessean (1812-1922)
New York Amsterdam News (1922-1993)
New York Times w/ Index (1851-2013)
Pittsburgh Courier (1911-2002)
The Wall Street Journal (1889-1999)
The Washington Post (1877-2000)
You might find some pertinent primary documents in these books.
(Attributed to Supa Snoopa)
Try searching these online video databases for your topic. As they say, "A picture is worth a thousand words."
A searchable and browsable database including approximately 1,000 hours of newsreels from the late 1890s to the 1980s. When complete it is expected to contain more than 2,000 hours of newsreel footage.
The HathiTrust is a partnership of major research institutions and libraries working to ensure that cultural records are preserved. Some items are full-text online and others are in print form; check our online catalog to see if we own them.
The Library of Congress's American Memory site has some great sports collections, especially of baseball. Here is one you might find useful.