New York, 22 April 1960 - Institutional correspondence A letter from Jan-Albert Goris to Nelson Rockefeller, dated 22 April 1960
New York, 25 April 1960 - Institutional correspondence Jan-Albert Goris's letter to Nelson Rockefeller, dated 25 April 1960
New York, 3 May 1968 - Institutional correspondence Dorothy C. Miller's letter to Daniel-Henry Kahnweiler
New York, 21 February 1966 - Management of reproduction rights Dorothy C. Miller's letter to Pearl Moeller