MLA
Gonne, Maud, 1866-1953. Letter written by Maud Gonne to William Butler Yeats - [late January 1899]. January 1899. 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/85370rxzms-cor.
APA, 6th edition
Gonne, Maud, 1866-1953. (January 1899)[Letter written by Maud Gonne to William Butler Yeats - [late January 1899]]. 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/85370rxzms-cor.
Chicago
Gonne, Maud, 1866-1953, Letter written by Maud Gonne to William Butler Yeats - [late January 1899], January 1899, 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/85370rxzms-cor.