United States. Department of the Treasury. "Bill Tender, December 15, 1969," in United States. Department of the Treasury. "Volume 167," Press Releases of the United States Department of the Treasury (November 7, 1969 - January 30, 1970) : 260-260. https://fraser.stlouisfed.org/title/6111/item/587010/toc/541612 , accessed on June 23, 2024.