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
Madrid, 1981 - Photograph Placing the reproduction of Guernica for the test installation in the Casón del Buen Retiro