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
Hollywood, 21 October 1939 - Institutional correspondence H. Heyman's and G. E. Scheyer's letter to Sidney Janis