Amsterdam, 16 January 1957 - Institutional correspondence A telegram from Willem Sandberg to Alfred H. Barr Jr.
New York, 23 January 1957 - Transport documents A letter from the vice-president of W. R. Keating & Company to Willem Sandberg
Amsterdam, 28 January 1957 - Institutional correspondence Willem Sandberg's letter to Robert Giron, dated 28 January 1957
Amsterdam, 28 January 1957 - Institutional correspondence Willem Sandberg's letter to Bo Wennberg, dated 28 January 1957
