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
New York, November 10, 1967 - Petition A Call for the Immediate Resignation of all the Rockefellers from the Museum of Modern Art’s Board of Trustees