Madrid, 22 April 1976 - Internal institutional documents A report by Joaquín de la Puente on the ownership of Guernica and the negotiation possibilities with the Museum of Modern Art, New York
Madrid, 10 September 1981 - Internal museum documents Certificate for the reception of Guernica, and its stretcher and related works
14 June 1997 - Newspapers The PNV (Basque Nationalist Party) secures a commitment from the PP (People's Party) for the temporary transfer of "Gernika" to Bilbao