MLA
Griffin, George C., 1897-1990. Letter from George Griffin giving to Emory Special Collections photocopies of James Atkins letters that he found in his father's papers. May 8, 1978. Civil War Collection. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/709w0vt5cf-cor.
APA, 6th edition
Griffin, George C., 1897-1990. (May 8, 1978)[Letter from George Griffin giving to Emory Special Collections photocopies of James Atkins letters that he found in his father's papers]. Civil War Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/709w0vt5cf-cor.
Chicago
Griffin, George C., 1897-1990, Letter from George Griffin giving to Emory Special Collections photocopies of James Atkins letters that he found in his father's papers, May 8, 1978, Civil War Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/709w0vt5cf-cor.