MLA
Seago, E. M., and W. L. Abbott. Letter of Recommendation from E. M. Seago and W. L. Abbot (Atlanta, Georgia), "To All Whom It May Concern," for William C. Loven. Seago and Abbott Served in the 20th Georgia Infantry Regiment - September 2, 1865. 1865. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 9, Folder 28. https://digital.library.emory.edu/purl/9182jm651g-cor.
APA, 6th edition
Seago, E. M., & Abbott, W. L. (1865). Letter of recommendation from E. M. Seago and W. L. Abbot (Atlanta, Georgia), "To all whom it may concern," for William C. Loven. Seago and Abbott served in the 20th Georgia Infantry Regiment - September 2, 1865 (Box 9, Folder 28) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/9182jm651g-cor.
Chicago
Seago, E. M, and W. L. Abbott. “Letter of Recommendation from E. M. Seago and W. L. Abbot (Atlanta, Georgia), ‘To All Whom It May Concern," for William C. Loven. Seago and Abbott Served in the 20th Georgia Infantry Regiment - September 2, 1865.” Letters (correspondence). Civil War Collection, 1865. Box 9, Folder 28. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/9182jm651g-cor.