MLA
Envelope Containing Letter from Christ C. McKinney (Camp in Tennessee) to His Wife, Mary (Petersburg, Tennessee). McKinney Served in the 8th Tennessee Infantry Regiment - November 16, 1862. 1862. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 5, Folder 7. https://digital.library.emory.edu/purl/238w9ghz42-cor.
APA, 6th edition
Envelope containing letter from Christ C. McKinney (Camp in Tennessee) to his wife, Mary (Petersburg, Tennessee). McKinney served in the 8th Tennessee Infantry Regiment - November 16, 1862 (Box 5, Folder 7). (1862). [Envelopes]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/238w9ghz42-cor.
Chicago
“Envelope Containing Letter from Christ C. McKinney (Camp in Tennessee) to His Wife, Mary (Petersburg, Tennessee). McKinney Served in the 8th Tennessee Infantry Regiment - November 16, 1862.” Envelopes. Civil War Collection, 1862. Box 5, Folder 7. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/238w9ghz42-cor.