New York, 12 March 1956 - Institutional correspondence Bernard Karpel's letter to Willem Sandberg, dated 12 March 1956
New York, 27 November 1956 - Institutional correspondence Bernard Karpel's letter to Willem Sandberg, dated 27 November 1956
Madrid, 1 September 1977 - Institutional correspondence A letter from Jesús Madalena to José Mario Armero
November 23 - 24, 2011 - Conferences and articles Timothy J. Clark. Otra mirada al Guernica (Another look at Guernica)