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, 5 November 1938 - Institutional correspondence Herman F. Reissig's letter to Julius Perlstein
New York, 1 November 1939 - Institutional correspondence Herman F. Reissig's letter to Marcelene Peterson, dated 1 November 1939
New York, 2 November 1939 - Institutional correspondence Herman F. Reissig's letter to Milton Wichner
New York, 17 November 1939 - Institutional correspondence Herman F. Reissig's letter to Marcelene Peterson, dated 17 November 1939