United States. Bureau of the Census. "Composite Indexes," in United States. Bureau of the Census. "June 1981," Business Conditions Digest (June 1981) : 16-17. https://fraser.stlouisfed.org/title/43/item/7418/toc/412338 , accessed on April 23, 2024.
United States. Bureau of the Census. "Composite Indexes," in United States. Bureau of the Census. "June 1981," Business Conditions Digest (June 1981) : 16-17. https://fraser.stlouisfed.org/title/43/item/7418/toc/412338 , accessed on April 23, 2024.