Sariñena (Huesca), 18 September 1936 - Institutional correspondence A letter from Francisco Ruiz (Jean Aaron) to Pablo Picasso
Cambridge, Massachusetts. 29 January 1940 - Institutional correspondence A letter from Paul Sachs to Alfred H. Barr Jr.
Barcelona, 4 February 1938 - Institutional correspondence Correspondence regarding the organisation of a Picasso exhibition in the USA