United States. Bureau of the Census. "Aggregate Series," in United States. Bureau of the Census. "July 1976," Business Conditions Digest (July 1976) : 90-90. https://fraser.stlouisfed.org/title/43/item/7359/toc/244154 , accessed on April 25, 2024.
United States. Bureau of the Census. "Aggregate Series," in United States. Bureau of the Census. "July 1976," Business Conditions Digest (July 1976) : 90-90. https://fraser.stlouisfed.org/title/43/item/7359/toc/244154 , accessed on April 25, 2024.