New York, 7 March 1956 - Institutional correspondence A telegram from Edgar Craig Schenk to Pablo Picasso
London, 18 April 1980 - Institutional correspondence Nicholas Serota's letter to Roland Penrose, dated 18 April 1980
London, 1 May 1980 - Institutional correspondence Nicholas Serota's letter to Roland Penrose, dated 1 May 1980