Madrid, 8 July 1972 - Institutional correspondence A letter from Xavier de Salas to Florentino Pérez Embid
ca. 1952–1956 - Internal museum documents Publicity report for the exhibition Studies for Guernica by Hamline University, addressed to the Travelling Exhibitions Department at the Museum of Modern Art, New York
New York, 22 February 1979 - Institutional correspondence Michael Blackwood's letter to Louise Kreisberg