New York, 9 September 1981 - Institutional correspondence An internal letter from Richard E. Oldenburg to staff at the Museum of Modern Art, New York
Amsterdam, 18 January 1956 - Transport documents Hans Ludwig Cohn Jaffé's letter to Holland-Amerika Lijn
Amsterdam, 17 October 1956 - Institutional correspondence A letter from Hans Ludwig Cohn Jaffé's to the editors of the newspaper De Tijd
New York, 24 March 1980 - Institutional correspondence A letter from Richard Oldenburg and William Rubin to Javier Tusell