United States. Department of the Treasury. "Bill Tender, June 23, 1969," in United States. Department of the Treasury. "Volume 165," Press Releases of the United States Department of the Treasury (May 6, 1969 - August 29, 1969) : 242-243. https://fraser.stlouisfed.org/title/6111/item/587008/toc/541469 , accessed on June 22, 2024.