United States. Bureau of the Census. "Aggregate Series," in United States. Bureau of the Census. "July 1972," Business Conditions Digest (July 1972) : 49-51. https://fraser.stlouisfed.org/title/43/item/7568/toc/328460 , accessed on May 3, 2024.
United States. Bureau of the Census. "Aggregate Series," in United States. Bureau of the Census. "July 1972," Business Conditions Digest (July 1972) : 49-51. https://fraser.stlouisfed.org/title/43/item/7568/toc/328460 , accessed on May 3, 2024.