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
Exhibition, MoMA, New York, June 2, 1967 – February 13, 1968 - Photograph View of the exhibition Guernica: Studies and Postscripts