MLA
King, and Baird. Union Patriotic Envelope - "We'Re the Boys That Fear No Noise." Published by King & Baird, 607 Sansom Street, Philadelphia. King & Baird, 1861. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 21, Folder 7. https://digital.library.emory.edu/purl/334fn2z49m-cor.
APA, 6th edition
K., & B. (1861). Union patriotic envelope - "We're the Boys that fear no Noise." Published by King & Baird, 607 Sansom Street, Philadelphia (Box 21, Folder 7) [Envelopes]. King & Baird; Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/334fn2z49m-cor.
Chicago
King, and Baird. “Union Patriotic Envelope - ‘We'Re the Boys That Fear No Noise." Published by King & Baird, 607 Sansom Street, Philadelphia.” Envelopes. Civil War Collection. Philadelphia, PA: King & Baird, 1861. Box 21, Folder 7. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/334fn2z49m-cor.