MLA
Mitchell, Stanley P. The Key of the Kingdom : True Theology. [S.P. Mitchell?], 1905. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/3720cfxqsk-cor.
APA, 6th edition
Mitchell, S. P. (1905). The key of the kingdom : true theology [African American author., African American pamphlet., African American publisher.]. [S.P. Mitchell?]; Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/3720cfxqsk-cor.
Chicago
Mitchell, Stanley P. “The Key of the Kingdom : True Theology.” African American author., African American pamphlet., African American publisher. African American Imprints Collection. [Memphis, Tenn.?]: [S.P. Mitchell?], 1905. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/3720cfxqsk-cor.