ca. 1952–1956 - Internal museum documents Publicity report for the exhibition Studies for Guernica by Hamline University, addressed to the Travelling Exhibitions Department at the Museum of Modern Art, New York
Ellen C. Oppler (ed.), <em>Picasso’s Guernica</em>, New York and London: W. W. Norton & Company, 1988, 236–238 - Essay “How Effective Is Social Protest Art? (Vietnam)”
Siracusa, New York, 15 July 1979 - Institutional correspondence Ellen Oppler's letter to Luisa Kreisberg