United States. Department of the Treasury. "Supplemental Duty Question and Answer Sheet No. 1, August 26, 1971," in United States. Department of the Treasury. "Volume 174," Press Releases of the United States Department of the Treasury (July 1, 1971 - August 31, 1971) : 558-562. https://fraser.stlouisfed.org/title/6111/item/587017/toc/542407 , accessed on June 25, 2024.