MLA
Walker, Charles T. (Charles Thomas), 1858-1921. Sequel to "The American Negro" : a reply to William Hannibal Thomas, author of a book recently published by McMillan Company, Fifth Ave., New York City, called "The American Negro". 1901. African American Imprints Collection. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/470zpc87bz-cor.
APA, 6th edition
Walker, Charles T. (Charles Thomas), 1858-1921. (1901)[Sequel to "The American Negro" : a reply to William Hannibal Thomas, author of a book recently published by McMillan Company, Fifth Ave., New York City, called "The American Negro"]. African American Imprints Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/470zpc87bz-cor.
Chicago
Walker, Charles T. (Charles Thomas), 1858-1921, Sequel to "The American Negro" : a reply to William Hannibal Thomas, author of a book recently published by McMillan Company, Fifth Ave., New York City, called "The American Negro", 1901, African American Imprints Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/470zpc87bz-cor.