United States. Bureau of the Census. "Cyclical Indicators," in United States. Bureau of the Census. "May 1970," Business Conditions Digest (May 1970) : 12-13. https://fraser.stlouisfed.org/title/43/item/7542/toc/271986 , accessed on April 25, 2024.
United States. Bureau of the Census. "Cyclical Indicators," in United States. Bureau of the Census. "May 1970," Business Conditions Digest (May 1970) : 12-13. https://fraser.stlouisfed.org/title/43/item/7542/toc/271986 , accessed on April 25, 2024.