Brussels, 17 February 1956 - Institutional correspondence Robert Giron's letter to Willem Sandberg, dated 17 February 1956
Brussels, 25 February 1956 - Institutional correspondence Robert Giron's letter to Willem Sandberg, dated 25 February 1956
Amsterdam, 21 March 1956 - Institutional correspondence Willem Sandberg's letter to Robert Giron, dated 21 March 1956
Brussels, 28 March 1956 - Insurance documents Robert Giron's letter to Willem Sandberg, dated 28 March 1956
Amsterdam, 4 April 1956 - Institutional correspondence Willem Sandberg's letter to Robert Giron, dated 4 April 1956
Brussels, 10 April 1956 - Institutional correspondence Robert Giron's letter to Willem Sandberg, dated 10 April 1956
Amsterdam, 11 April 1956 - Institutional correspondence Willem Sandberg's letter to Robert Giron, dated 11 April 1956
Amsterdam, 11 January 1956 - Transport documents Willem Sandberg's letter to Holland-Amerika Lijn, dated 11 January 1956
Amsterdam, 11 January 1956 - Institutional correspondence Willem Sandberg's letter to Robert Giron, dated 11 January 1956
Roxbury, 12 January 1956 - Institutional correspondence Alexander Calder's letter to Willem Sandberg, dated 12 January 1956
Rotterdam, 13 January 1956 - Transport documents A letter from Holland-Amerika Lijnto to Willem Sandberg, dated 13 January 1956
Amsterdam, 23 January 1956 - Institutional correspondence Willem Sandberg's letter to Alexander Calder, dated 23 January 1956
Amsterdam, 21 February 1956 - Transport documents Willem Sandberg's letter to Holland-Amerika Lijn, dated 21 February 1956
Amsterdam, 24 February 1956 - Institutional correspondence Willem Sandberg's letter to Bernard Karpel, dated 24 February 1956
Amsterdam, 25 February 1956 - Transport documents Willem Sandberg's letter to Holland-Amerika Lijn, dated 25 February 1956
Amsterdam, 27 February 1956 - Institutional correspondence Willem Sandberg's letter to Amsterdam City Council, dated 27 February 1956
New York, 12 March 1956 - Institutional correspondence Bernard Karpel's letter to Willem Sandberg, dated 12 March 1956
Amsterdam, 19 March 1956 - Institutional correspondence Willem Sandberg's letter to René d'Harnoncourt
Amsterdam, 19 March 1956 - Institutional correspondence Willem Sandberg's letter to the Valentin Gallery
Brussels, 4 April 1956 - Institutional correspondence Robert Giron's letter to Willem Sandberg, dated 4 April 1956