United States. Department of the Treasury. "Market Transactions, September 14, 1967, Release Number f-1025," in United States. Department of the Treasury. "Volume 159," Press Releases of the United States Department of the Treasury (September 1, 1967 - November 29, 1967) : 45-46. https://fraser.stlouisfed.org/title/6111/item/587002/toc/540642 , accessed on May 6, 2024.