United States. Department of the Treasury. "U.S. Treasury To Sell Silver, April 12, 1989, Release Number nb-220," in United States. Department of the Treasury. "Volume 290," Press Releases of the United States Department of the Treasury (April 3, 1989 - May 3, 1989) : 54-56. https://fraser.stlouisfed.org/title/6111/item/587133/toc/535695 , accessed on June 26, 2024.