United States. Bureau of the Census. "Other Economic Measures," in United States. Bureau of the Census. "May 1987," Business Conditions Digest (May 1987) : 14-15. https://fraser.stlouisfed.org/title/43/item/7489/toc/392422 , accessed on May 7, 2024.
United States. Bureau of the Census. "Other Economic Measures," in United States. Bureau of the Census. "May 1987," Business Conditions Digest (May 1987) : 14-15. https://fraser.stlouisfed.org/title/43/item/7489/toc/392422 , accessed on May 7, 2024.