MLA
Son, D. Murphy's. Union Patriotic Envelope with Jefferson Davis Cartoon - "The Traitor Arnold Giving a Warm Reception to the Traitor Davis", Published D. Murphy's Son. D. Murphy's Son, Print, 1861. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 21, Folder 4. https://digital.library.emory.edu/purl/187pnvx1rx-cor.
APA, 6th edition
Son, D. M. (1861). Union patriotic envelope with Jefferson Davis cartoon - "The Traitor Arnold giving a warm reception to the Traitor Davis", published D. Murphy's Son (Box 21, Folder 4) [Envelopes]. D. Murphy's Son, Print; Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/187pnvx1rx-cor.
Chicago
Son, D. Murphy's. “Union Patriotic Envelope with Jefferson Davis Cartoon - ‘The Traitor Arnold Giving a Warm Reception to the Traitor Davis’, Published D. Murphy's Son.” Envelopes. Civil War Collection. New York City, NY: D. Murphy's Son, Print, 1861. Box 21, Folder 4. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/187pnvx1rx-cor.