MLA
Ruggles, Daniel, 1810-1897. Letter from Daniel Ruggles (Laredo, Texas) to the son of one of his friends advising him as to his future and telling him of his own war experiences and his subsequent life - August 26, 1875. August 26, 1875. Civil War Collection. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/501pg4f5g5-cor.
APA, 6th edition
Ruggles, Daniel, 1810-1897. (August 26, 1875)[Letter from Daniel Ruggles (Laredo, Texas) to the son of one of his friends advising him as to his future and telling him of his own war experiences and his subsequent life - August 26, 1875]. Civil War Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/501pg4f5g5-cor.
Chicago
Ruggles, Daniel, 1810-1897, Letter from Daniel Ruggles (Laredo, Texas) to the son of one of his friends advising him as to his future and telling him of his own war experiences and his subsequent life - August 26, 1875, August 26, 1875, Civil War Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/501pg4f5g5-cor.