United States. Bureau of the Census. "Table of Contents," in United States. Bureau of the Census. "June 1981," Business Conditions Digest (June 1981) : 3-4. https://fraser.stlouisfed.org/title/43/item/7418/toc/412333 , accessed on April 25, 2024.
United States. Bureau of the Census. "Table of Contents," in United States. Bureau of the Census. "June 1981," Business Conditions Digest (June 1981) : 3-4. https://fraser.stlouisfed.org/title/43/item/7418/toc/412333 , accessed on April 25, 2024.