MLA
Godfrey, Caroline Hardee. Letter by Caroline Hardee Godfrey to "Dear Didu[?]". Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 3, Folder 37. https://digital.library.emory.edu/purl/4988gthv64-cor.
APA, 6th edition
Godfrey, C. H. Letter by Caroline Hardee Godfrey to "Dear Didu[?]" (Box 3, Folder 37) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/4988gthv64-cor.
Chicago
Godfrey, Caroline Hardee. “Letter by Caroline Hardee Godfrey to ‘Dear Didu[?]".” Letters (correspondence). Civil War Collection, n.d. Box 3, Folder 37. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/4988gthv64-cor.