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, 8 November 1955 - Institutional correspondence Willem Sandberg's letter to Alexander Calder, dated 8 November 1955
Amsterdam, 30 November 1955 - Institutional correspondence Willem Sandberg's letter to Alexander Calder, dated 30 November 1955
Amsterdam, 3 December 1955 - Institutional correspondence Willem Sandberg's letter to Dora Maar, dated 3 December 1955
Paris, 5 December 1955 - Institutional correspondence Maurice Lefebvre-Foinet's letter to Willem Sandberg
Zurich, 12 December 1955 - Institutional correspondence A letter from Klaus Herdeg to Willem Sandberg
Amsterdam, 16 December 1955 - Institutional correspondence Willem Sandberg's letter to Dora Maar, dated 16 December 1955
Roxbury, 12 January 1956 - Institutional correspondence Alexander Calder's letter to Willem Sandberg, dated 12 January 1956
Paris, 3 November 1980 - Institutional correspondence Dominique Bozo's letter to Josep Lluís Sert, dated 3 November 1980
Cambridge, Massachusetts, 29 November 1980 - Institutional correspondence Josep Lluís Sert's letter to Dominique Bozo
Paris, 23 December 1980 - Institutional correspondence Dominique Bozo's letter to Josep Lluís Sert, dated 23 December 1980
Madrid, 31 July, and Cambridge, Massachusetts, 31 August 1981 - Institutional correspondence Álvaro Martínez Novillo's letter to Josep Lluís Sert, with reply
Valencia, 27 February 1981 - Institutional correspondence A letter from Manuel García y García to Javier Tusell, dated 27 February 1981
Valencia, 23 June 1981 - Institutional correspondence A letter from Manuel García y García to Javier Tusell, dated 23 June 1981