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
30 May 1996 - Newspapers The Spanish Government and the PNV (Basque Nationalist Party) discuss the transfer of Guernica