United States. Department of the Treasury. "Bill Tender, May 28, 1957," in United States. Department of the Treasury. "Volume 110," Press Releases of the United States Department of the Treasury (May 2, 1957 - July 26, 1957) : 68-72. https://fraser.stlouisfed.org/title/6111/item/586953/toc/537381 , accessed on June 25, 2024.