MLA
Union Patriotic Envelope - "Stand By The Flag - Let Every Man's Motto Be:-'I Am with My Country, and for My Country, under All Circumstances, and in Every Contingency.'". 1861. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 21, Folder 7. https://digital.library.emory.edu/purl/8773tx972b-cor.
APA, 6th edition
Union patriotic envelope - "Stand By The Flag - Let every man's motto be:-'I am with my Country, and for my Country, under all circumstances, and in every contingency.'" (Box 21, Folder 7). (1861). [Envelopes]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/8773tx972b-cor.
Chicago
“Union Patriotic Envelope - ‘Stand By The Flag - Let Every Man's Motto Be:-'I Am with My Country, and for My Country, under All Circumstances, and in Every Contingency.'".” Envelopes. Civil War Collection, 1861. Box 21, Folder 7. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/8773tx972b-cor.