United States. Department of the Treasury. "Lead and Zinc, July 14, 1965, Release Number f-122," in United States. Department of the Treasury. "Volume 149," Press Releases of the United States Department of the Treasury (June 1, 1965 - July 30, 1965) : 598-600. https://fraser.stlouisfed.org/title/6111/item/586992/toc/539774 , accessed on June 23, 2024.