United States. Bureau of the Census. "Aggregate Series," in United States. Bureau of the Census. "June 1973," Business Conditions Digest (June 1973) : 90-90. https://fraser.stlouisfed.org/title/43/item/7322/toc/166913 , accessed on March 28, 2024.
United States. Bureau of the Census. "Aggregate Series," in United States. Bureau of the Census. "June 1973," Business Conditions Digest (June 1973) : 90-90. https://fraser.stlouisfed.org/title/43/item/7322/toc/166913 , accessed on March 28, 2024.