Madrid, 10 September 1981 - Internal museum documents Certificate for the reception of Guernica, and its stretcher and related works
Paris, 6 September 1939 - Institutional correspondence Christian Zervos's letter to Alfred H. Barr Jr., dated 6 September 1939
Paris, 27 December 1939 - Institutional correspondence Christian Zervos's letter to Alfred H. Barr Jr., dated 27 December 1939
Paris, 26 October 1939 - Institutional correspondence Christian Zervos's letter to Alfred H. Barr Jr., dated 26 October 1939