Chicago, 21 February 1955 - Management of reproduction rights Marilyn Vaughan's letter to Pablo Picasso
Charlotte, 27 January 1967 - Institutional correspondence Constance H. Nicholson's letter to Carol K. Uht
22 November 1980 - Institutional correspondence Rafael Fernández Quintanilla's letter to Javier Tusell, dated 22 November 1980