61. Proposed Mining Projects, by Robert Smithson. c.1972-3. Chromogenic Print (Made from a Slide). (Archives of American Art, Washington; Exh. International Center for Photography, New York).
Attributed works:
62. Nonsite (Slag), Oberhausen, Germany, 1968, by Robert Smithson. Gelatin-Silver Print. (Archives of American Art, Washington; Exh. International Center for Photography, New York).