Cleveland, 25 May 1939 - Institutional correspondence William Mathewson Milliken's letter to Sidney Janis
1940 - Internal museum documents Circulating exhibition contract for Picasso: Forty Years of His Art (second edition), between the Museum of Modern Art, New York, and the Cleveland Museum of Art
New York: Praeger Publishers Inc., 1973 - Essay Six Years: The Dematerialization of the Art Object from 1966 to 1972