New York, 10 July 1939 - Institutional correspondence Blanche Mahler's letter to Grace L. McCann Morley
2 May 1939 - Internal institutional documents A draft text for the invitation to the exhibition Picasso's Guernica at the Valentine Gallery, New York
<em>The New York Times</em>, New York, September 28, 1969, section D, 35 - Article “Keeping Art On The Streets”