United States. Bureau of the Census. "Table of Contents," in United States. Bureau of the Census. "March 1971," Business Conditions Digest (March 1971) : 3-4. https://fraser.stlouisfed.org/title/43/item/7552/toc/289426 , accessed on April 18, 2024.
United States. Bureau of the Census. "Table of Contents," in United States. Bureau of the Census. "March 1971," Business Conditions Digest (March 1971) : 3-4. https://fraser.stlouisfed.org/title/43/item/7552/toc/289426 , accessed on April 18, 2024.