Madrid, 2 December 1975 and Berkeley, California, 8 January 1976 - Institutional correspondence A letter from José Mario Armero to Herschel B. Chip, with reply
16 September 1960 - Internal museum documents A letter from Betsy Jones to Alfred H. Barr Jr., dated 16 September 1960
New York, 6 August 1973 - Institutional correspondence A letter from Betsy Jones to Daniel-Henry Kahnweiler
New York, 18 September 1964 - Institutional correspondence A letter from Betsy Jones to Alfred H. Barr Jr., dated 18 September 1964