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
Madrid, 21 February 1969 - Institutional correspondence Florentino Pérez-Embid's letter to Joaquín de la Fuente