United States. Bureau of the Census. "Title Page," in United States. Bureau of the Census. "December 1971," Business Conditions Digest (December 1971) : 2-2. https://fraser.stlouisfed.org/title/43/item/7561/toc/77152 , accessed on May 10, 2024.
United States. Bureau of the Census. "Title Page," in United States. Bureau of the Census. "December 1971," Business Conditions Digest (December 1971) : 2-2. https://fraser.stlouisfed.org/title/43/item/7561/toc/77152 , accessed on May 10, 2024.