MLA
Leigh M., Richar_[?]. Letter from Richard McLeigh to John T. Champney - June 15, 1862. 1862. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 2, Folder 12. https://digital.library.emory.edu/purl/4881jwsvph-cor.
APA, 6th edition
Leigh M., R. (1862). Letter from Richard McLeigh to John T. Champney - June 15, 1862 (Box 2, Folder 12) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/4881jwsvph-cor.
Chicago
Leigh M., Richar_[?]. “Letter from Richard McLeigh to John T. Champney - June 15, 1862.” Letters (correspondence). Civil War Collection, 1862. Box 2, Folder 12. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/4881jwsvph-cor.