MLA
Rogers, J. P. Letter from J. P. Rogers (Camp near Tunnel Hill, Georgia) to "Dear Father" (North Bend, Alabama) - March 9, 1864. 1864. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 6, Folder 2. https://digital.library.emory.edu/purl/163stqjqqr-cor.
APA, 6th edition
Rogers, J. P. (1864). Letter from J. P. Rogers (Camp near Tunnel Hill, Georgia) to "Dear Father" (North Bend, Alabama) - March 9, 1864 (Box 6, Folder 2) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/163stqjqqr-cor.
Chicago
Rogers, J. P. “Letter from J. P. Rogers (Camp near Tunnel Hill, Georgia) to ‘Dear Father’ (North Bend, Alabama) - March 9, 1864.” Letters (correspondence). Civil War Collection, 1864. Box 6, Folder 2. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/163stqjqqr-cor.