United States. Bureau of the Census. "Composite Indexes," in United States. Bureau of the Census. "April 1988," Business Conditions Digest (April 1988) : 66-66. https://fraser.stlouisfed.org/title/43/item/7500/toc/188287 , accessed on June 29, 2024.
United States. Bureau of the Census. "Composite Indexes," in United States. Bureau of the Census. "April 1988," Business Conditions Digest (April 1988) : 66-66. https://fraser.stlouisfed.org/title/43/item/7500/toc/188287 , accessed on June 29, 2024.