United States. Bureau of the Census. "Cover Page," in United States. Bureau of the Census. "March 1981," Business Conditions Digest (March 1981) : 1-1. https://fraser.stlouisfed.org/title/43/item/7415/toc/261262 , accessed on July 15, 2024.
United States. Bureau of the Census. "Cover Page," in United States. Bureau of the Census. "March 1981," Business Conditions Digest (March 1981) : 1-1. https://fraser.stlouisfed.org/title/43/item/7415/toc/261262 , accessed on July 15, 2024.