United States. Bureau of the Census. "Foreign Trade," in United States. Bureau of the Census. "March 1969," Business Conditions Digest (March 1969) : 72-72. https://fraser.stlouisfed.org/title/43/item/7528/toc/62154 , accessed on May 7, 2024.
United States. Bureau of the Census. "Foreign Trade," in United States. Bureau of the Census. "March 1969," Business Conditions Digest (March 1969) : 72-72. https://fraser.stlouisfed.org/title/43/item/7528/toc/62154 , accessed on May 7, 2024.