Milan, 4 August 1953 - Institutional correspondence A letter from Fernanda Wittgens to Willem Sandberg, dated 4 August 1953
Milan, 12 August 1953 - Institutional correspondence Fernanda Wittgens' letter to Willem Sandberg, dated 12 August 1953
Milan, 7 October 1953 - Institutional correspondence A letter from Fernanda Wittgens to Willem Sandberg, dated 7 October 1953
Stockholm, 1956 - Photograph Photographs of the assembly of the exhibition Guernica, avec 60 études in the Nationalmuseum, Stockholm
Gernika, 6 April and Madrid, 9 April 1987 - Institutional correspondence Correspondence on the Gernika 37-87 commemoration acts