United States. Bureau of the Census. "Cyclical Indicators," in United States. Bureau of the Census. "May 1988," Business Conditions Digest (May 1988) : 12-14. https://fraser.stlouisfed.org/title/43/item/7501/toc/40612 , accessed on April 23, 2024.
United States. Bureau of the Census. "Cyclical Indicators," in United States. Bureau of the Census. "May 1988," Business Conditions Digest (May 1988) : 12-14. https://fraser.stlouisfed.org/title/43/item/7501/toc/40612 , accessed on April 23, 2024.