United States. Bureau of the Census. "Foreign Trade," in United States. Bureau of the Census. "March 1969," Business Conditions Digest (March 1969) : 19-19. https://fraser.stlouisfed.org/title/43/item/7528/toc/62124 , accessed on April 25, 2024.
United States. Bureau of the Census. "Foreign Trade," in United States. Bureau of the Census. "March 1969," Business Conditions Digest (March 1969) : 19-19. https://fraser.stlouisfed.org/title/43/item/7528/toc/62124 , accessed on April 25, 2024.