Madrid, 8 July 1972 - Institutional correspondence A letter from Xavier de Salas to Florentino Pérez Embid
Paris, 30 October 1971 - Institutional correspondence A letter from Luis López Ballesteros to Alfredo Sánchez Bella
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