MLA
Gonne, Maud, 1866-1953. Letter written by Maud Gonne to William Butler Yeats - October 22, 1897. October 22, 1897. Maud Gonne and W.B. Yeats Papers, circa 1890-1938. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/1848pk0r4h-cor.
APA, 6th edition
Gonne, Maud, 1866-1953. (October 22, 1897)[Letter written by Maud Gonne to William Butler Yeats - October 22, 1897]. Maud Gonne and W.B. Yeats Papers, circa 1890-1938, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/1848pk0r4h-cor.
Chicago
Gonne, Maud, 1866-1953, Letter written by Maud Gonne to William Butler Yeats - October 22, 1897, October 22, 1897, Maud Gonne and W.B. Yeats Papers, circa 1890-1938, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/1848pk0r4h-cor.