MLA
Weeks, A. B. Letter from A. B. Weeks (Enterprise, Mississippi), to His Wife and Children. Weeks Served in Captain Samuel G. Bain's Vaiden (Mississippi) Light Artillery - October 26, 1863. 1863. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 7, Folder 16. https://digital.library.emory.edu/purl/098z8w9hj8-cor.
APA, 6th edition
Weeks, A. B. (1863). Letter from A. B. Weeks (Enterprise, Mississippi), to his wife and children. Weeks served in Captain Samuel G. Bain's Vaiden (Mississippi) Light Artillery - October 26, 1863 (Box 7, Folder 16) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/098z8w9hj8-cor.
Chicago
Weeks, A. B. “Letter from A. B. Weeks (Enterprise, Mississippi), to His Wife and Children. Weeks Served in Captain Samuel G. Bain's Vaiden (Mississippi) Light Artillery - October 26, 1863.” Letters (correspondence). Civil War Collection, 1863. Box 7, Folder 16. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/098z8w9hj8-cor.