ca. 1952–1956 - Internal museum documents Publicity report for the exhibition Studies for Guernica by the School of Fine and Applied Arts, Columbus, Ohio, addressed to the Travelling Exhibitions Department at the Museum of Modern Art, New York
New York, 4 May 1950 - Institutional correspondence Joseph Schwartz's letter to the Museum of Modern Art, New York
Gerti Fietzek (ed.), Cologne: Buchhandlung Walther König, 2009 - Essay Maria Eichhorn. The Artist's Contract