MLA
Hedge, F. Union Patriotic Envelope - Officer[?] Holding the United States Flag, Published by F. Hedge SC. F. Hedge SC., 1861. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 21, Folder 7. https://digital.library.emory.edu/purl/972p5hqd4k-cor.
APA, 6th edition
Hedge, F. (1861). Union patriotic envelope - Officer[?] holding the United States flag, published by F. Hedge SC. (Box 21, Folder 7) [Envelopes]. F. Hedge SC.; Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/972p5hqd4k-cor.
Chicago
Hedge, F. “Union Patriotic Envelope - Officer[?] Holding the United States Flag, Published by F. Hedge SC.” Envelopes. Civil War Collection. Boston, MA: F. Hedge SC., 1861. Box 21, Folder 7. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/972p5hqd4k-cor.