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.
Joseph Lancaster (1807). “Improvements in Education, as it Respects the Industrious Classes of the Community: Containing Among Other Important Particulars, an Account of the Institution for the Education of One Thousand Poor Children, Borough Road, Southwark; and of the New System of Education on which it is Conducted”, p.151