ca. 1952–1957 - Internal museum documents Publicity report for the exhibition Studies for Guernica by the Museum of Cranbrook, New Jersey, 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)”
<em>The New York Review of Books</em>, New York, May 6, 1971 - Article “Judgment Deferred on Lieutenant Calley”
Siracusa, New York, 15 July 1979 - Institutional correspondence Ellen Oppler's letter to Luisa Kreisberg