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
Artistic project, 7th Berlin Biennale for Contemporary Art, April 27 – July 1, 2012 - Website Occupy Biennale