Madrid, 17 September 1980 - Institutional correspondence A letter from José Mario Armero to Íñigo Cavero
New York, 5 June 1939 - Institutional correspondence Evelyn Ahrend's letter to Alfred H. Barr Jr., dated 5 June 1939
New York, 14 June 1939 - Institutional correspondence Evelyn Ahrend's letter to Alfred H. Barr Jr., dated 14 June 1939