New York, 9 July 1956 - Institutional correspondence Alfred H. Barr Jr.'s letter to Pablo Picasso, dated 9 July 1956
New York, 31 March 1956 - Institutional correspondence Alfred H. Barr Jr.'s letter to Pablo Picasso, dated 31 March 1956
New York, 12 May 1956 - Institutional correspondence Alfred H. Barr Jr.'s letter to Pablo Picasso, dated 12 May 1956
October - December 1956 - Photograph Photograph of the installation of the exhibition Guernica, avec 60 études at the Nationalmuseum, Stockholm