MLA
Thayer, George A. (George Augustine), 1839-1925. History of the Second Massachusetts Regiment of Infantry, Chancellorsville : a paper read at the officers' reunion in Boston, May 11, 1880. 1882. Regimental Histories. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/095j9kd8v2-cor.
APA, 6th edition
Thayer, George A. (George Augustine), 1839-1925. (1882)[History of the Second Massachusetts Regiment of Infantry, Chancellorsville : a paper read at the officers' reunion in Boston, May 11, 1880]. Regimental Histories, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/095j9kd8v2-cor.
Chicago
Thayer, George A. (George Augustine), 1839-1925, History of the Second Massachusetts Regiment of Infantry, Chancellorsville : a paper read at the officers' reunion in Boston, May 11, 1880, 1882, Regimental Histories, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/095j9kd8v2-cor.