United States. Bureau of the Census. "Foreign Trade," in United States. Bureau of the Census. "April 1969," Business Conditions Digest (April 1969) : 19-19. https://fraser.stlouisfed.org/title/43/item/7529/toc/216883 , accessed on April 23, 2024.
United States. Bureau of the Census. "Foreign Trade," in United States. Bureau of the Census. "April 1969," Business Conditions Digest (April 1969) : 19-19. https://fraser.stlouisfed.org/title/43/item/7529/toc/216883 , accessed on April 23, 2024.