United States. Bureau of the Census. "Cover Page," in United States. Bureau of the Census. "July 1981," Business Conditions Digest (July 1981) : 1-1. https://fraser.stlouisfed.org/title/43/item/7419/toc/226031 , accessed on April 19, 2024.
United States. Bureau of the Census. "Cover Page," in United States. Bureau of the Census. "July 1981," Business Conditions Digest (July 1981) : 1-1. https://fraser.stlouisfed.org/title/43/item/7419/toc/226031 , accessed on April 19, 2024.