United States. Bureau of the Census. "Foreign Trade (chart)," in United States. Bureau of the Census. "May 1987," Business Conditions Digest (May 1987) : 50-50. https://fraser.stlouisfed.org/title/43/item/7489/toc/392440 , accessed on May 4, 2024.
United States. Bureau of the Census. "Foreign Trade (chart)," in United States. Bureau of the Census. "May 1987," Business Conditions Digest (May 1987) : 50-50. https://fraser.stlouisfed.org/title/43/item/7489/toc/392440 , accessed on May 4, 2024.