Brussels, 14 May 1956 - Institutional correspondence A letter from the Spanish ambassador in Belgium to Alberto Martín-Artajo Álvarez
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