Paris, 29 September 1955 - Institutional correspondence Daniel-Henry Kahnweiler's letter to Willem Sandberg, dated 29 September 1955
Roxbury, 22 November 1955 - Institutional correspondence Alexander Calder's letter to Willem Sandberg, dated 22 November 1955
1956 - Conferences and articles Text by Kahnweiler for the exhibition catalogue Guernica avec 60 études
Roxbury, 12 January 1956 - Institutional correspondence Alexander Calder's letter to Willem Sandberg, dated 12 January 1956
Paris, 22 May 1956 - Institutional correspondence Daniel-Henry Kahnweiler's letter to Willem Sandberg, dated 22 May 1956