United States. Bureau of the Census. "Analytical Ratios," in United States. Bureau of the Census. "May 1972," Business Conditions Digest (May 1972) : 68-68. https://fraser.stlouisfed.org/title/43/item/7566/toc/88820 , accessed on May 4, 2024.
United States. Bureau of the Census. "Analytical Ratios," in United States. Bureau of the Census. "May 1972," Business Conditions Digest (May 1972) : 68-68. https://fraser.stlouisfed.org/title/43/item/7566/toc/88820 , accessed on May 4, 2024.