United States. Bureau of the Census. "Composite Indexes," in United States. Bureau of the Census. "June 1987," Business Conditions Digest (June 1987) : 16-17. https://fraser.stlouisfed.org/title/43/item/7490/toc/321698 , accessed on March 28, 2024.
United States. Bureau of the Census. "Composite Indexes," in United States. Bureau of the Census. "June 1987," Business Conditions Digest (June 1987) : 16-17. https://fraser.stlouisfed.org/title/43/item/7490/toc/321698 , accessed on March 28, 2024.