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, 12 Julio 1971 - Institutional correspondence A letter from Juan Antonio Cánovas del Castillo to Florentino Pérez-Embid