Madrid, 2 December 1975 and Berkeley, California, 8 January 1976 - Institutional correspondence A letter from José Mario Armero to Herschel B. Chip, with reply
Charlotte, 27 January 1967 - Institutional correspondence Constance H. Nicholson's letter to Carol K. Uht
New York, 8 April 1981 - Press release and communication A press release from New York's Museum of Modern Art concerning a Spanish delegation's request to send Guernica to Spain