MLA
Letcher, John. Certification of Robert Mercer Taliaferro Hunter, as Confederate States Senator for Virginia, Signed by John Letcher (Richmond, Virginia) - February 15, 1862. 1862. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 4, Folder 43. https://digital.library.emory.edu/purl/0515mkkxfj-cor.
APA, 6th edition
Letcher, J. (1862). Certification of Robert Mercer Taliaferro Hunter, as Confederate States Senator for Virginia, signed by John Letcher (Richmond, Virginia) - February 15, 1862 (Box 4, Folder 43) [Certificates]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/0515mkkxfj-cor.
Chicago
Letcher, John. “Certification of Robert Mercer Taliaferro Hunter, as Confederate States Senator for Virginia, Signed by John Letcher (Richmond, Virginia) - February 15, 1862.” Certificates. Civil War Collection, 1862. Box 4, Folder 43. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/0515mkkxfj-cor.