MLA
Clarke's Confederate Almanac for the Year of Our Lord 1865 : Being Bissextile, or Leap Year, and the Fifth Year of the Independence of the Confederate States : Calculations Made for All the Southern States, with Accurate Accounts of the Great Eclipses, &c. H.C. Clarke, 1864. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/122v41nwr7-cor.
APA, 6th edition
Clarke's Confederate almanac for the year of our Lord 1865 : being bissextile, or leap year, and the fifth year of the independence of the Confederate States : calculations made for all the Southern states, with accurate accounts of the great eclipses, &c. (1864). [Almanacs, Southern imprint]. H.C. Clarke; Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/122v41nwr7-cor.
Chicago
“Clarke's Confederate Almanac for the Year of Our Lord 1865 : Being Bissextile, or Leap Year, and the Fifth Year of the Independence of the Confederate States : Calculations Made for All the Southern States, with Accurate Accounts of the Great Eclipses, &c.” Almanacs, Southern imprint. Civil War Imprints. Mobile, Ala.: H.C. Clarke, 1864. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/122v41nwr7-cor.