ca. 1952–1956 - Internal museum documents Publicity report for the exhibition Studies for Guernica by the University of Minnesota Gallery, addressed to the Travelling Exhibitions Department at the Museum of Modern Art, New York
12 September 1981 - Newspapers Protests in the Basque Country over the installation of Guernica in the Casón del Buen Retiro
Gerti Fietzek (ed.), Cologne: Buchhandlung Walther König, 2009 - Essay Maria Eichhorn. The Artist's Contract