New York, 10 March 1955 - Institutional correspondence Alfred H. Barr Jr.'s letter to Pablo Picasso, dated 10 March 1955
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
Stockholm, 23 October 1956 - Institutional correspondence Ernesto de Zulueta's letter to Alberto Martín-Artajo Álvarez
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
Meudon, 19 November 1955 - Institutional correspondence Nelly Van Doesburg's letter to Louise Boyer, dated 19 November 1955
New York, 9 July 1956 - Institutional correspondence Alfred H. Barr Jr.'s letter to Pablo Picasso, dated 9 July 1956
New York, 20 February 1956 - Institutional correspondence Alfred H. Barr Jr.'s letter to Nelson Rockefeller
Copenhagen, 31 October 1956 - Institutional correspondence Lars Rostrup Boyesen's letter to Pablo Picasso
Paris, 10 February 1955 - Institutional correspondence Daniel-Henry Kahnweiler's letter to Alfred H. Barr Jr., dated 10 February 1955