- 1) Bingham to Mr. Blitzer, “Cancellation, American exhibition, X Bienal de Sao Paulo.” July 18, 1969.
- 2) U.S. Information Agency, “Following is background for guidance any queries generated by failure U.S. participate Sao Paulo Bienal.” August 19, 1969.
- 3) U.S. Information Agency, “Perhaps matters could be left at that.” September 3, 1969.