Amsterdam, 16 November 1953 - Institutional correspondence Willem Sandberg's letter to Pablo Picasso, dated 16 November 1953
Amsterdam, 5 May 1953 - Institutional correspondence Willem Sandberg's letter to Eugenio Reale, dated 5 May 1953
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
Amsterdam, 18 August 1953 - Institutional correspondence Willem Sandberg's letter to Eugenio Reale, dated 18 August 1953
Amsterdam, 11 September 1953 - Institutional correspondence Willem Sandberg's letter to Fernanda Wittgens
Milan, 7 October 1953 - Institutional correspondence A letter from Fernanda Wittgens to Willem Sandberg, dated 7 October 1953
