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
ca. 1952–1956 - Internal museum documents Publicity report for the exhibition Studies for Guernica by Allegheny College, Meadville, Pennsylvania, addressed to the Travelling Exhibitions Department at the Museum of Modern Art, New York