16 September 1960 - Internal museum documents A letter from Betsy Jones to Alfred H. Barr Jr., dated 16 September 1960
Madrid, 19 October 1977 - Institutional correspondence Antonio Fontán Pérez's letter to Adolfo Suárez
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