New York, 9 September 1981 - Institutional correspondence An internal letter from Richard E. Oldenburg to staff at the Museum of Modern Art, New York
Madrid, 16 June 1988 - Internal institutional documents Iñaki Anasagasti's questions to the Congress of Deputies
New York, 24 March 1980 - Institutional correspondence A letter from Richard Oldenburg and William Rubin to Javier Tusell