MLA
Union Patriotic Envelopes Dealing with Secession - "The Real Secession Flag". 1861. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 21, Folder 8. https://digital.library.emory.edu/purl/0924b8gvmx-cor.
APA, 6th edition
Union patriotic envelopes dealing with secession - "The real secession flag" (Box 21, Folder 8). (1861). [Envelopes]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/0924b8gvmx-cor.
Chicago
“Union Patriotic Envelopes Dealing with Secession - ‘The Real Secession Flag.’” Envelopes. Civil War Collection, 1861. Box 21, Folder 8. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/0924b8gvmx-cor.