United States. Bureau of the Census. "Analytical Measures," in United States. Bureau of the Census. "July 1970," Business Conditions Digest (July 1970) : 14-14. https://fraser.stlouisfed.org/title/43/item/7544/toc/187166 , accessed on May 4, 2024.
United States. Bureau of the Census. "Analytical Measures," in United States. Bureau of the Census. "July 1970," Business Conditions Digest (July 1970) : 14-14. https://fraser.stlouisfed.org/title/43/item/7544/toc/187166 , accessed on May 4, 2024.