Paris, 29 September 1955 - Institutional correspondence Daniel-Henry Kahnweiler's letter to Willem Sandberg, dated 29 September 1955
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
Milan, 7 October 1953 - Institutional correspondence A letter from Fernanda Wittgens to Willem Sandberg, dated 7 October 1953
Paris, 29 September 1955 - Institutional correspondence Daniel-Henry Kahnweiler's letter to Robert Giron
1956 - Conferences and articles Text by Kahnweiler for the exhibition catalogue Guernica avec 60 études
Paris, 22 May 1956 - Institutional correspondence Daniel-Henry Kahnweiler's letter to Willem Sandberg, dated 22 May 1956