United States. Bureau of the Census. "Foreign Trade," in United States. Bureau of the Census. "June 1970," Business Conditions Digest (June 1970) : 52-52. https://fraser.stlouisfed.org/title/43/item/7543/toc/266695 , accessed on April 18, 2024.
United States. Bureau of the Census. "Foreign Trade," in United States. Bureau of the Census. "June 1970," Business Conditions Digest (June 1970) : 52-52. https://fraser.stlouisfed.org/title/43/item/7543/toc/266695 , accessed on April 18, 2024.