United States. Bureau of the Census. "Cyclical Indicators," in United States. Bureau of the Census. "April 1977," Business Conditions Digest (April 1977) : 13-15. https://fraser.stlouisfed.org/title/43/item/7368/toc/49189 , accessed on May 9, 2024.
United States. Bureau of the Census. "Cyclical Indicators," in United States. Bureau of the Census. "April 1977," Business Conditions Digest (April 1977) : 13-15. https://fraser.stlouisfed.org/title/43/item/7368/toc/49189 , accessed on May 9, 2024.