United States. Department of the Treasury. "Lead and Zinc, February 12, 1960," in United States. Department of the Treasury. "Volume 120," Press Releases of the United States Department of the Treasury (January 5, 1960 - March 31, 1960) : 182-185. https://fraser.stlouisfed.org/title/6111/item/586963/toc/538129 , accessed on June 24, 2024.