MLA
Son, D. Murphy's. Union Patriotic Envelopes Dealing with Secession - "SECESSION WHISKEY. One Does Warranted to Kill, at 40 Rods." Published by D. Murphy's Sons. D. Murphy's Son, Print, 1861. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 21, Folder 8. https://digital.library.emory.edu/purl/53976hdsfv-cor.
APA, 6th edition
Son, D. M. (1861). Union patriotic envelopes dealing with secession - "SECESSION WHISKEY. One does warranted to kill, at 40 rods." Published by D. Murphy's Sons (Box 21, Folder 8) [Envelopes]. D. Murphy's Son, Print; Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/53976hdsfv-cor.
Chicago
Son, D. Murphy's. “Union Patriotic Envelopes Dealing with Secession - ‘SECESSION WHISKEY. One Does Warranted to Kill, at 40 Rods." Published by D. Murphy's Sons.” Envelopes. Civil War Collection. New York City, NY: D. Murphy's Son, Print, 1861. Box 21, Folder 8. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/53976hdsfv-cor.