United States. Bureau of the Census. "Aggregate Series," in United States. Bureau of the Census. "June 1974," Business Conditions Digest (June 1974) : 90-90. https://fraser.stlouisfed.org/title/43/item/7334/toc/353987 , accessed on March 28, 2024.
United States. Bureau of the Census. "Aggregate Series," in United States. Bureau of the Census. "June 1974," Business Conditions Digest (June 1974) : 90-90. https://fraser.stlouisfed.org/title/43/item/7334/toc/353987 , accessed on March 28, 2024.