New York, 9 September 1981 - Institutional correspondence An internal letter from Richard E. Oldenburg to staff at the Museum of Modern Art, New York
New York, 24 March 1980 - Institutional correspondence A letter from Richard Oldenburg and William Rubin to Javier Tusell
New York, 8 May 1968 - Institutional correspondence Antonio Serrano's letter to Fernando María Castiella
August-September 1990 - Institutional correspondence Correspondence on an exhibition project in Hiroshima