United States. Bureau of the Census. "Cyclical Indicators," in United States. Bureau of the Census. "March 1977," Business Conditions Digest (March 1977) : 13-15. https://fraser.stlouisfed.org/title/43/item/7367/toc/276385 , accessed on May 7, 2024.
United States. Bureau of the Census. "Cyclical Indicators," in United States. Bureau of the Census. "March 1977," Business Conditions Digest (March 1977) : 13-15. https://fraser.stlouisfed.org/title/43/item/7367/toc/276385 , accessed on May 7, 2024.