United States. Department of the Treasury. "Bill Tender, September 2, 1966, Release Number f-606," in United States. Department of the Treasury. "Volume 155," Press Releases of the United States Department of the Treasury (August 1, 1966 - October 31, 1966) : 244-245. https://fraser.stlouisfed.org/title/6111/item/586998/toc/540266 , accessed on June 23, 2024.