Paris, 2 November 1979 - Personal correspondence A copy of a letter Claude Picasso wrote to William Rubin, director of Painting and Sculpture at MoMA
Paris, 1 March 1975 - Personal correspondence Claude Picasso's letter to William S. Lieberman, dated 1 March 1975
New York, 27 August 1980 - Institutional correspondence A letter from Eleanor L. Saxe to William Rubin, Sharon Zane and others