United States. Bureau of the Census. "Analytical Measures," in United States. Bureau of the Census. "July 1969," Business Conditions Digest (July 1969) : 14-14. https://fraser.stlouisfed.org/title/43/item/7532/toc/358085 , accessed on May 5, 2024.
United States. Bureau of the Census. "Analytical Measures," in United States. Bureau of the Census. "July 1969," Business Conditions Digest (July 1969) : 14-14. https://fraser.stlouisfed.org/title/43/item/7532/toc/358085 , accessed on May 5, 2024.