United States. Bureau of the Census. "Analytical Measures," in United States. Bureau of the Census. "May 1975," Business Conditions Digest (May 1975) : 34-34. https://fraser.stlouisfed.org/title/43/item/7345/toc/405855 , accessed on June 27, 2024.
United States. Bureau of the Census. "Analytical Measures," in United States. Bureau of the Census. "May 1975," Business Conditions Digest (May 1975) : 34-34. https://fraser.stlouisfed.org/title/43/item/7345/toc/405855 , accessed on June 27, 2024.