United States. Department of the Treasury. "Office of Tariff Affairs," in United States. Department of the Treasury. "Annual Report of the Secretary of the Treasury on the State of the Finances, Fiscal Year 1979," Annual Report of the Secretary of the Treasury on the State of the Finances (Fiscal Year Ended September 30, 1979) : 236-237. https://fraser.stlouisfed.org/title/194/item/5624/toc/370736 , accessed on April 18, 2024.