1955 - Press release and communication Thirty individual collectors and eight national museums in Europe and the United States contribute paintings for the first Picasso retrospective in Paris since the war
23 May 1955 - Press release and communication A press release on the opening of the exhibition Picasso at the Musée des Arts Décoratifs, Paris
Rotterdam, 13 January 1956 - Transport documents A letter from Holland-Amerika Lijnto to Willem Sandberg, dated 13 January 1956
Rotterdam, 4 April 1956 - Transport documents A letter from Holland-Amerika Lijn to Willem Sandberg, dated 4 April 1956
Rotterdam, 20 December 1956 - Transport documents A letter from Holland-Amerika Lijn to Willem Sandberg, dated 20 December 1956
Rotterdam, 1956 - Transport documents A packing list for the delivery of 6 boxes with Guernica and studies from Amsterdam to New York
Rotterdam, 1956 - Transport documents A contract from the transport company Holland-Amerika Lijn for the delivery of Guernica and studies to New York
Ellen C. Oppler (ed.), <em>Picasso’s Guernica</em>, New York and London: W. W. Norton & Company, 1988, 236–238 - Essay “How Effective Is Social Protest Art? (Vietnam)”
Siracusa, New York, 15 July 1979 - Institutional correspondence Ellen Oppler's letter to Luisa Kreisberg