MLA
Couch, Sarah, et al. Letter from S. M. Couch, Sarah J. Couch and Sarah Couch to "Dear Mother" (Arminda Couch) - June 9, 1860. 1860. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 2, Folder 29. https://digital.library.emory.edu/purl/7956djhbx6-cor.
APA, 6th edition
Couch, S., Couch, S. M., & Couch, S. J. (1860). Letter from S. M. Couch, Sarah J. Couch and Sarah Couch to "Dear Mother" (Arminda Couch) - June 9, 1860 (Box 2, Folder 29) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/7956djhbx6-cor.
Chicago
Couch, Sarah, S. M. Couch, and Sarah J. Couch. “Letter from S. M. Couch, Sarah J. Couch and Sarah Couch to ‘Dear Mother’ (Arminda Couch) - June 9, 1860.” Letters (correspondence). Civil War Collection, 1860. Box 2, Folder 29. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/7956djhbx6-cor.