W. E. B. Du Bois (2014). “The Problem of the Color Line at the Turn of the Twentieth Century: The Essential Early Essays”, p.59, Oxford University Press
W. E. B. Du Bois, Frederick Douglass, Booker T. Washington (2012). “Three African-American Classics: Up from Slavery, The Souls of Black Folk and Narrative of the Life of Frederick Douglass”, p.329, Courier Corporation
W. E. B. Du Bois (2014). “The Problem of the Color Line at the Turn of the Twentieth Century: The Essential Early Essays”, p.61, Oxford University Press