United States. Department of the Treasury. "Lead and Zinc, July 16, 1959," in United States. Department of the Treasury. "Volume 118," Press Releases of the United States Department of the Treasury (July 2, 1959 - September 29, 1959) : 50-52. https://fraser.stlouisfed.org/title/6111/item/586961/toc/537963 , accessed on June 25, 2024.