United States. Bureau of the Census. "Analytical Ratios," in United States. Bureau of the Census. "March 1972," Business Conditions Digest (March 1972) : 67-67. https://fraser.stlouisfed.org/title/43/item/7564/toc/378581 , accessed on May 3, 2024.
United States. Bureau of the Census. "Analytical Ratios," in United States. Bureau of the Census. "March 1972," Business Conditions Digest (March 1972) : 67-67. https://fraser.stlouisfed.org/title/43/item/7564/toc/378581 , accessed on May 3, 2024.