United States. Bureau of the Census. "Analytical Ratios," in United States. Bureau of the Census. "June 1972," Business Conditions Digest (June 1972) : 68-68. https://fraser.stlouisfed.org/title/43/item/7567/toc/381432 , accessed on April 23, 2024.
United States. Bureau of the Census. "Analytical Ratios," in United States. Bureau of the Census. "June 1972," Business Conditions Digest (June 1972) : 68-68. https://fraser.stlouisfed.org/title/43/item/7567/toc/381432 , accessed on April 23, 2024.