United States. Bureau of the Census. "Foreign Trade," in United States. Bureau of the Census. "July 1970," Business Conditions Digest (July 1970) : 52-52. https://fraser.stlouisfed.org/title/43/item/7544/toc/187186 , accessed on April 25, 2024.
United States. Bureau of the Census. "Foreign Trade," in United States. Bureau of the Census. "July 1970," Business Conditions Digest (July 1970) : 52-52. https://fraser.stlouisfed.org/title/43/item/7544/toc/187186 , accessed on April 25, 2024.