MLA
Union Patriotic Envelopes Dealing with Secession - Upside down United States Flag, "May Emblems of Traitors, Ever Scurvy / Be Forever Topsy-Turvy.". 1861. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 21, Folder 8. https://digital.library.emory.edu/purl/3418kprs93-cor.
APA, 6th edition
Union patriotic envelopes dealing with secession - Upside down United States Flag, "May emblems of traitors, ever scurvy / Be forever topsy-turvy." (Box 21, Folder 8). (1861). [Envelopes]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/3418kprs93-cor.
Chicago
“Union Patriotic Envelopes Dealing with Secession - Upside down United States Flag, ‘May Emblems of Traitors, Ever Scurvy / Be Forever Topsy-Turvy.".” Envelopes. Civil War Collection, 1861. Box 21, Folder 8. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/3418kprs93-cor.