New York, 7 March 1956 - Institutional correspondence A telegram from Edgar Craig Schenk to Pablo Picasso
Yonkers, 20 March 1969 - Institutional correspondence Donald M. Jr. Halley's letter to Nelson Rockefeller
Oslo, 27 November 1956 - Institutional correspondence A letter from Miguel de Aldasoro to Alberto Martín-Artajo Álvarez