Mougins, 14 November 1970 - Institutional correspondence Pablo Picasso's letter to the New York's Museum of Modern Art
Paris, 3 October 1948 - Institutional correspondence Pablo Picasso's letter to Alfred H. Barr Jr., dated 3 October 1948
Pars, 9 February 1955 - Institutional correspondence Pablo Picasso's letter to Alfred H. Barr Jr., dated 9 February 1955
Amsterdam and Brussels, 1956 - Exhibition catalogue Guernica: avec 60 études et variantesGuernica: met 60 studies et varianten
New York, 5 July 1956 - Institutional correspondence William S. Lieberman's letter to Richard Griffith
New York, 20 September 1956 - Institutional correspondence William S. Lieberman's letter to Alfred H. Barr Jr.
Berlin, 1975 - Exhibition catalogue Exhibition catalogue for Kunst und Politik am Beispiel Guernica. Picasso und der Spanische Bürgerkrieg
New York, 31 May 1977 - Institutional correspondence William S. Lieberman's letter to Richard Oldenburg, dated 31 May 1977
New York, 1 June 1977 - Institutional correspondence William S. Lieberman's letter to Richard Oldenburg, dated 1 June 1977
New York, 7 June 1977 - Institutional correspondence William S. Lieberman's letter to Richard Oldenburg, dated 7 June 1977