1955 - Internal institutional documents A list of works for the Picasso exhibition, which will travel from Paris to Munich
15 June 1956 - Invoices An invoice from R. Lerondelle for the delivery of the works arriving from 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