United States. Bureau of the Census. "Aggregate Series," in United States. Bureau of the Census. "July 1975," Business Conditions Digest (July 1975) : 54-55. https://fraser.stlouisfed.org/title/43/item/7347/toc/239362 , accessed on May 4, 2024.
United States. Bureau of the Census. "Aggregate Series," in United States. Bureau of the Census. "July 1975," Business Conditions Digest (July 1975) : 54-55. https://fraser.stlouisfed.org/title/43/item/7347/toc/239362 , accessed on May 4, 2024.