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, 7 March 1956 - Institutional correspondence A telegram from Edgar Craig Schenk to Pablo Picasso
New York, 24 March 1980 - Institutional correspondence A letter from Richard Oldenburg and William Rubin to Javier Tusell