Letter of Archibald Butt to Clara F. Butt on June 01, 1909. "Taft and Roosevelt: The intimate letters of Archie Butt" by Archibald Willingham Butt, 1930.
George Washington (1860). “Recollections and private memoirs of Washington by his adopted son George Washington with a memoir of the author by his daughter; and illustrative and explanatory notes by Benson J. Loosing: With illustrations”, p.77