W. E. B. Du Bois (2013). “Black Reconstruction in America: Toward a History of the Part Which Black Folk Played in the Attempt to Reconstruct Democracy in America, 1860-1880”, p.650, Transaction Publishers
Booker T. Washington, W. E. B. Du Bois, Frederick Douglass (2007). “Three African-American Classics: Up from Slavery, The Souls of Black Folk and Narrative of the Life of Frederick Douglass”, p.279, Courier Corporation
W. E. B. Du Bois' statement of 1910, as quoted in Gregory Michael Dorr "Fighting Fire with Fire: African Americans and Hereditarian Thinking, 1900-1942" by Gregory Michael Dorr on Wake Forest University Homepage, March 13, 2006.
W. E. B. Du Bois (2014). “The Problem of the Color Line at the Turn of the Twentieth Century: The Essential Early Essays”, p.67, Oxford University Press