MLA
Smith, Henry Wright, 1828-. Union general George B. McClellan. 1861?/1880?. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/197xksn18z-cor.
APA, 6th edition
Smith, Henry Wright, 1828-. (1861?/1880?)[Union general George B. McClellan]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/197xksn18z-cor.
Chicago
Smith, Henry Wright, 1828-, Union general George B. McClellan, 1861?/1880?, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/197xksn18z-cor.