United States. Bureau of the Census. "Composite Indexes," in United States. Bureau of the Census. "March 1987," Business Conditions Digest (March 1987) : 16-17. https://fraser.stlouisfed.org/title/43/item/7487/toc/298703 , accessed on May 9, 2024.
United States. Bureau of the Census. "Composite Indexes," in United States. Bureau of the Census. "March 1987," Business Conditions Digest (March 1987) : 16-17. https://fraser.stlouisfed.org/title/43/item/7487/toc/298703 , accessed on May 9, 2024.