New York, 12 March 1956 - Institutional correspondence Bernard Karpel's letter to Willem Sandberg, dated 12 March 1956
New York, 27 November 1956 - Institutional correspondence Bernard Karpel's letter to Willem Sandberg, dated 27 November 1956
Horseheads, New York, 23 January 1956 - Management of reproduction rights Hugh Thomas's letter to Alfred H. Barr Jr.