MLA
Union Patriotic Envelope - Bald Eagle Holding a Shield, "Stand By The Flag". 1861. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 21, Folder 7. https://digital.library.emory.edu/purl/11615dv593-cor.
APA, 6th edition
Union patriotic envelope - Bald eagle holding a shield, "Stand By The Flag" (Box 21, Folder 7). (1861). [Envelopes]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/11615dv593-cor.
Chicago
“Union Patriotic Envelope - Bald Eagle Holding a Shield, ‘Stand By The Flag.’” Envelopes. Civil War Collection, 1861. Box 21, Folder 7. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/11615dv593-cor.