United States. Bureau of the Census. "Diffusion Indexes," in United States. Bureau of the Census. "March 1977," Business Conditions Digest (March 1977) : 43-45. https://fraser.stlouisfed.org/title/43/item/7367/toc/276398 , accessed on May 6, 2024.
United States. Bureau of the Census. "Diffusion Indexes," in United States. Bureau of the Census. "March 1977," Business Conditions Digest (March 1977) : 43-45. https://fraser.stlouisfed.org/title/43/item/7367/toc/276398 , accessed on May 6, 2024.