United States. Bureau of the Census. "Table of Contents," in United States. Bureau of the Census. "May 1981," Business Conditions Digest (May 1981) : 3-4. https://fraser.stlouisfed.org/title/43/item/7417/toc/358978 , accessed on March 28, 2024.
United States. Bureau of the Census. "Table of Contents," in United States. Bureau of the Census. "May 1981," Business Conditions Digest (May 1981) : 3-4. https://fraser.stlouisfed.org/title/43/item/7417/toc/358978 , accessed on March 28, 2024.