New York, 9 September 1981 - Institutional correspondence An internal letter from Richard E. Oldenburg to staff at the Museum of Modern Art, New York
22 November 1980 - Institutional correspondence Rafael Fernández Quintanilla's letter to Javier Tusell, dated 22 November 1980
New York, 24 March 1980 - Institutional correspondence A letter from Richard Oldenburg and William Rubin to Javier Tusell