1992-1993 - Internal museum documents Exhibition folder. Picasso: The Love and the Anguish. The Road to Guernica
September to October 1981 - Institutional correspondence Ten letters, telegrams, and some poems sent to congratulate the arrival of Picasso's Guernica at the Museo del Prado
1988-1992 - Internal museum documents Arranging the Collection: The transfer of Pablo Picasso's Guernica to the Centro de Arte Reina Sofía
New York, 22 November 1969 - Institutional correspondence A letter from William S. Lieberman to Roland Dumas
New York, 7 March 1956 - Institutional correspondence William S. Lieberman's letter to Porter McCrary
New York, 20 September 1956 - Institutional correspondence William S. Lieberman's letter to Alfred H. Barr Jr.
New York, 7 June 1977 - Institutional correspondence William S. Lieberman's letter to Richard Oldenburg, dated 7 June 1977
New York, 1 June 1977 - Institutional correspondence William S. Lieberman's letter to Richard Oldenburg, dated 1 June 1977
New York, 31 May 1977 - Institutional correspondence William S. Lieberman's letter to Richard Oldenburg, dated 31 May 1977
New York, 5 July 1956 - Institutional correspondence William S. Lieberman's letter to Richard Griffith