The file comprises letters, 1968-[1998], from foreign repositories including the Albright-Knox Gallery, Buffalo, New York; Archives of American Art, Detroit; Art Gallery of Ontario; Brooklyn College; University of California, Los Angeles; Davis & Langdale Company, New York; Department of National Defence, Ottawa; Dunedin Public Art Gallery, New Zealand; Havard University Archives; Houghton Library, Havard University; Huntington, California; University of Michigan; Mount Holyoke College, Massachusetts; Musée Picasso, Paris; Musée Rodin, Paris; New York Public Library; Johannesburg Art Gallery; South African National Gallery; University of Auckland; University of Texas and Yale University Library, and also letters, 1996, from his book publishers Farrar, Straus & Giroux in New York.