MLA
Envelope Addressed to Confederate General Wilmot Gibbes De Saussure. 1861. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 3, Folder 3. https://digital.library.emory.edu/purl/419s1rn9pk-cor.
APA, 6th edition
Envelope addressed to Confederate General Wilmot Gibbes de Saussure (Box 3, Folder 3). (1861). [Envelopes]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/419s1rn9pk-cor.
Chicago
“Envelope Addressed to Confederate General Wilmot Gibbes De Saussure.” Envelopes. Civil War Collection, 1861. Box 3, Folder 3. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/419s1rn9pk-cor.