Paris, 29 September 1955 - Institutional correspondence Daniel-Henry Kahnweiler's letter to Willem Sandberg, dated 29 September 1955
Amsterdam, 8 November 1955 - Institutional correspondence Willem Sandberg's letter to Josep Lluís Sert
Roxbury, 22 November 1955 - Institutional correspondence Alexander Calder's letter to Willem Sandberg, dated 22 November 1955
Cambridge, Massachusetts, 8 December 1955 - Institutional correspondence Josep Lluís Sert's letter to Willem Sandberg
Amsterdam, 5 May 1953 - Institutional correspondence Willem Sandberg's letter to Eugenio Reale, dated 5 May 1953
Milan, 4 August 1953 - Institutional correspondence A letter from Fernanda Wittgens to Willem Sandberg, dated 4 August 1953
Milan, 12 August 1953 - Institutional correspondence Fernanda Wittgens' letter to Willem Sandberg, dated 12 August 1953
Amsterdam, 18 August 1953 - Institutional correspondence Willem Sandberg's letter to Eugenio Reale, dated 18 August 1953
Amsterdam, 11 September 1953 - Institutional correspondence Willem Sandberg's letter to Fernanda Wittgens
Milan, 7 October 1953 - Institutional correspondence A letter from Fernanda Wittgens to Willem Sandberg, dated 7 October 1953
New York, 24 September 1954 - Institutional correspondence Alfred H. Barr Jr.'s letter to Roland Penrose, dated 24 September 1954
Paris, 29 September 1955 - Institutional correspondence Daniel-Henry Kahnweiler's letter to Robert Giron
Amsterdam, 11 October 1955 - Institutional correspondence Willem Sandberg's letter to Daniel-Henry Kahnweiler, dated 11 October 1955
Amsterdam, 8 November 1955 - Institutional correspondence Willem Sandberg's letter to Alexander Calder, dated 8 November 1955