25 September and 11 October 1972 - Personal correspondence A letter from Catherine Freedberg to Roland Penrose, including the reply
Madrid, 5 November 1980 - Institutional correspondence A letter from Íñigo Cavero to Blanche de Philip P. Weisberg (Blanche Mahler)
30 June 1981 - Institutional correspondence Letters from Íñigo Cavero to Pablo Picasso's heirs, dated 30 June 1981
Madrid, 13 June 1981 - Institutional correspondence Letters from Íñigo Cavero Pablo Picasso's heirs, dated 13 June 1981
Madrid, 10 September 1981 - Internal museum documents Certificate for the reception of Guernica, and its stretcher and related works
Cambridge, Massachusetts, 14 May 1973 - Institutional correspondence Catherine Freedberg's letter to Patricia Failing