MLA
Graham, John P. Letter from John P. Graham (Chattanooga, Tennessee) to His Wife, Susan Frances Story Graham - October 10, 1863 (Photocopy). 1863. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 3, Folder 39. https://digital.library.emory.edu/purl/13331zcskf-cor.
APA, 6th edition
Graham, J. P. (1863). Letter from John P. Graham (Chattanooga, Tennessee) to his wife, Susan Frances Story Graham - October 10, 1863 (photocopy) (Box 3, Folder 39) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/13331zcskf-cor.
Chicago
Graham, John P. “Letter from John P. Graham (Chattanooga, Tennessee) to His Wife, Susan Frances Story Graham - October 10, 1863 (Photocopy).” Letters (correspondence). Civil War Collection, 1863. Box 3, Folder 39. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/13331zcskf-cor.