United States. Bureau of the Census. "Aggregate Series," in United States. Bureau of the Census. "June 1975," Business Conditions Digest (June 1975) : 54-55. https://fraser.stlouisfed.org/title/43/item/7346/toc/263739 , accessed on May 11, 2024.
United States. Bureau of the Census. "Aggregate Series," in United States. Bureau of the Census. "June 1975," Business Conditions Digest (June 1975) : 54-55. https://fraser.stlouisfed.org/title/43/item/7346/toc/263739 , accessed on May 11, 2024.