Copenhagen, 31 October 1956 - Institutional correspondence Lars Rostrup Boyesen's letter to Pablo Picasso
Baden-Baden, 1 July 1955 - Institutional correspondence A letter from the director of the Gesellschaft der Freunde junger Kunst Baden-Baden to the Musée des Arts Décoratifs
Copenhagen, 31 October 1956 - Institutional correspondence Lars Rostrup Boyesen's letter to Daniel-Henry Kahnweiler
Copenhagen, 31 October 1956 - Institutional correspondence Lars Rostrup Boyesen's letter to the Museum of Modern Art, New York