Newspapers can be very useful for your research because they are so very current, with the major papers publishing every day.
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)