United States. Bureau of the Census. "Composite Indexes," in United States. Bureau of the Census. "April 1980," Business Conditions Digest (April 1980) : 66-66. https://fraser.stlouisfed.org/title/43/item/7404/toc/372971 , accessed on May 9, 2024.
United States. Bureau of the Census. "Composite Indexes," in United States. Bureau of the Census. "April 1980," Business Conditions Digest (April 1980) : 66-66. https://fraser.stlouisfed.org/title/43/item/7404/toc/372971 , accessed on May 9, 2024.