MLA
Vaughn, John C. Circular Letter from John C. Vaughn "To the People of the 7th Senatorial District" (Sweet Water, Monroe County, Tennessee), Regarding Slavery and Why It Is a Moral Good - January 29, 1861. 1861. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 3, Folder 7. https://digital.library.emory.edu/purl/740ksn03zd-cor.
APA, 6th edition
Vaughn, J. C. (1861). Circular letter from John C. Vaughn "To the people of the 7th Senatorial District" (Sweet Water, Monroe County, Tennessee), regarding slavery and why it is a moral good - January 29, 1861 (Box 3, Folder 7) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/740ksn03zd-cor.
Chicago
Vaughn, John C. “Circular Letter from John C. Vaughn ‘To the People of the 7th Senatorial District’ (Sweet Water, Monroe County, Tennessee), Regarding Slavery and Why It Is a Moral Good - January 29, 1861.” Letters (correspondence). Civil War Collection, 1861. Box 3, Folder 7. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/740ksn03zd-cor.