MLA
Ward, Joseph W. Letter from Joseph W. Ward (Fernandina, Florida) to His Father. Ward Was an Officer in Company L of the 24th Mississippi Infantry - December 25, 1861. 1861. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 7, Folder 12. https://digital.library.emory.edu/purl/088qbzkj27-cor.
APA, 6th edition
Ward, J. W. (1861). Letter from Joseph W. Ward (Fernandina, Florida) to his father. Ward was an officer in Company L of the 24th Mississippi Infantry - December 25, 1861 (Box 7, Folder 12) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/088qbzkj27-cor.
Chicago
Ward, Joseph W. “Letter from Joseph W. Ward (Fernandina, Florida) to His Father. Ward Was an Officer in Company L of the 24th Mississippi Infantry - December 25, 1861.” Letters (correspondence). Civil War Collection, 1861. Box 7, Folder 12. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/088qbzkj27-cor.