MLA
Griffin, Marvin, 1907-1982. Proclamation for observing September 23, 1958 as William Thomas Overby day in the state of Georgia (94th death anniversary of William Thomas Overby, a member of Mosby's Rangers and hanged by the Federal Army in 1864); signed by Marvin Griffin, Governor of Georgia - September 17, 1958. September 17, 1958. Civil War Collection. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/948sbcc3j8-cor.
APA, 6th edition
Griffin, Marvin, 1907-1982. (September 17, 1958)[Proclamation for observing September 23, 1958 as William Thomas Overby day in the state of Georgia (94th death anniversary of William Thomas Overby, a member of Mosby's Rangers and hanged by the Federal Army in 1864); signed by Marvin Griffin, Governor of Georgia - September 17, 1958]. Civil War Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/948sbcc3j8-cor.
Chicago
Griffin, Marvin, 1907-1982, Proclamation for observing September 23, 1958 as William Thomas Overby day in the state of Georgia (94th death anniversary of William Thomas Overby, a member of Mosby's Rangers and hanged by the Federal Army in 1864); signed by Marvin Griffin, Governor of Georgia - September 17, 1958, September 17, 1958, Civil War Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/948sbcc3j8-cor.