Amsterdam, 16 November 1953 - Institutional correspondence Willem Sandberg's letter to Pablo Picasso, dated 16 November 1953
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
São Paulo, 4 March 1953 - Institutional correspondence Arturo Profili's letter to Paulo E. de Berrêdo Carneiro, dated 4 March 1953
New York, 15 June 1953 - Institutional correspondence Alfred H. Barr Jr.'s letter to Daniel-Henry Kahnweiler, dated 15 June 1953
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
Milan, 1953 - Internal museum documents An expense inventory for the Pablo Picasso exhibition at the Palazzo Reale