Paris, 31 May 1937 - Internal institutional documents Summary of figures submitted as payment for propaganda
Paris, 31 May 1937 - Internal institutional documents Figures submitted by the Special Acquisitions Service for Propaganda
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