MLA
Brown, C. P. A. Letter from C. P. A. Brown to South Carolina Governor Johnson Hagood - March 7, 1882. 1882. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 8, Folder 31. https://digital.library.emory.edu/purl/361rfj6qvf-cor.
APA, 6th edition
Brown, C. P. A. (1882). Letter from C. P. A. Brown to South Carolina Governor Johnson Hagood - March 7, 1882 (Box 8, Folder 31) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/361rfj6qvf-cor.
Chicago
Brown, C. P. A. “Letter from C. P. A. Brown to South Carolina Governor Johnson Hagood - March 7, 1882.” Letters (correspondence). Civil War Collection, 1882. Box 8, Folder 31. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/361rfj6qvf-cor.