^ Architect of the Capitol Under the Direction of the Joint Committee on the Library, Compilation of Works of Art and Other Objects in the United States Capitol, United States Government Printing Office, Washington, 1965, p. 212.
^ Cooley, Adelaide N. ‘’The Monument Maker: A Biography of Frederick Ernest Triebel, The rediscovery of a forgotten American sculptor’’ Exposition Press, Hicksville NY, 1978, pp. 19–20.
^ Murdock, Myrtle Chaney, National Statuary Hall in the Nation’s Capitol, Monumental Press, Inc., Washington, D.C., 1955, pp. 28–29.