MLA
Putnam, George Palmer, 1814-1872. Letters from Europe touching the American contest : and acknowledging the receipt, from citizens of New York, of presentation sets of the "Rebellion record," and "Loyal publication society" publications.. 1864. Civil War Imprints. Emory University. General Libraries. https://digital.library.emory.edu/purl/4407wm3bw7-cor.
APA, 6th edition
Putnam, George Palmer, 1814-1872. (1864)[Letters from Europe touching the American contest : and acknowledging the receipt, from citizens of New York, of presentation sets of the "Rebellion record," and "Loyal publication society" publications.]. Civil War Imprints, Emory University. General Libraries. https://digital.library.emory.edu/purl/4407wm3bw7-cor.
Chicago
Putnam, George Palmer, 1814-1872, Letters from Europe touching the American contest : and acknowledging the receipt, from citizens of New York, of presentation sets of the "Rebellion record," and "Loyal publication society" publications., 1864, Civil War Imprints, Emory University. General Libraries. https://digital.library.emory.edu/purl/4407wm3bw7-cor.