Stockholm, 23 October 1956 - Institutional correspondence Ernesto de Zulueta's letter to Alberto Martín-Artajo Álvarez
Paris, 10 December 1975 - Institutional correspondence Miguel de Lojendio's letter to Spain's Ministry of Culture
Paris, 29 September 1945 - Institutional correspondence A letter from the secretary of the Association des Intellectuels italiens in France to Pablo Picasso