MLA
Bailey, A. F. Letter from Austin F. Bailey (Camp near Brandy Station, Virginia) to His Parents Regarding Troop Movements, Food, Weather, Morale, and Tent Mates. Austin F. Bailey Served in the 1st Vermont Cavalry - February 6, 1862. 1862. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 19, Folder 2. https://digital.library.emory.edu/purl/6623bk3kfb-cor.
APA, 6th edition
Bailey, A. F. (1862). Letter from Austin F. Bailey (Camp near Brandy Station, Virginia) to his parents regarding troop movements, food, weather, morale, and tent mates. Austin F. Bailey served in the 1st Vermont Cavalry - February 6, 1862 (Box 19, Folder 2) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/6623bk3kfb-cor.
Chicago
Bailey, A. F. “Letter from Austin F. Bailey (Camp near Brandy Station, Virginia) to His Parents Regarding Troop Movements, Food, Weather, Morale, and Tent Mates. Austin F. Bailey Served in the 1st Vermont Cavalry - February 6, 1862.” Letters (correspondence). Civil War Collection, 1862. Box 19, Folder 2. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/6623bk3kfb-cor.