20 February 1980 - Institutional correspondence A letter from Ricardo de la Cierva Hoces to Adolfo Suárez
Madrid, 28 June 1980 - Institutional correspondence Ricardo de la Cierva Hoces' letter to Javier Tusell
New York, 24 October 1945 - Institutional correspondence A letter from Curt Valentin to Roland Penrose
ca. 1952–1956 - Internal museum documents Publicity report for the exhibition Studies for Guernica by the Lowe Gallery, Miami University, addressed to the Travelling Exhibitions Department at the Museum of Modern Art, New York