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
Report, La Sexta Noticias, January 21, 2016 - News programme “Declarados culpables de fiasco económico los gestores de la ‘Bienal de arte’ de Sevilla” (The managers of the Art Biennial of Seville found guilty of a “financial fiasco”)