United States. Department of the Treasury. "Bill Offering, April 19, 1967, Release Number f-882," in United States. Department of the Treasury. "Volume 157," Press Releases of the United States Department of the Treasury (March 1, 1967 - May 31, 1967) : 408-410. https://fraser.stlouisfed.org/title/6111/item/587000/toc/540563 , accessed on June 2, 2024.