Madrid, 24 September 1936 - Institutional correspondence Letter from Josep Renau to Pablo Picasso, 24 September 1936
Paris, 2 November 1979 - Personal correspondence A copy of a letter Claude Picasso wrote to William Rubin, director of Painting and Sculpture at MoMA
<em>The New York Times</em>, New York, September 28, 1969, section D, 35 - Article “Keeping Art On The Streets”
Paris, 1 March 1975 - Personal correspondence Claude Picasso's letter to William S. Lieberman, dated 1 March 1975