MLA
Brown, L. M. Letter from L. M. Brown (Company I of the 32nd North Carolina Regiment, Grimes Brigade, Petersburg, Virginia) to "Cousin Ann" - January 20, 1865. 1865. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 1, Folder 40. https://digital.library.emory.edu/purl/317crjdgmz-cor.
APA, 6th edition
Brown, L. M. (1865). Letter from L. M. Brown (Company I of the 32nd North Carolina Regiment, Grimes Brigade, Petersburg, Virginia) to "Cousin Ann" - January 20, 1865 (Box 1, Folder 40) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/317crjdgmz-cor.
Chicago
Brown, L. M. “Letter from L. M. Brown (Company I of the 32nd North Carolina Regiment, Grimes Brigade, Petersburg, Virginia) to ‘Cousin Ann’ - January 20, 1865.” Letters (correspondence). Civil War Collection, 1865. Box 1, Folder 40. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/317crjdgmz-cor.