MLA
Walthall, Fannie H. Letter from Fannie H. Walthall (Vicksburg, Mississippi) to William E. Mickle - April 22, 1904. 1904. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 9, Folder 17. https://digital.library.emory.edu/purl/426m0cfzsj-cor.
APA, 6th edition
Walthall, F. H. (1904). Letter from Fannie H. Walthall (Vicksburg, Mississippi) to William E. Mickle - April 22, 1904 (Box 9, Folder 17) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/426m0cfzsj-cor.
Chicago
Walthall, Fannie H. “Letter from Fannie H. Walthall (Vicksburg, Mississippi) to William E. Mickle - April 22, 1904.” Letters (correspondence). Civil War Collection, 1904. Box 9, Folder 17. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/426m0cfzsj-cor.