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
21 May 1976 - Personal correspondence Letter from Tomàs Llorens to Claude Picasso within the context of the Venice Biennale