United States. Bureau of the Census. "Diffusion Indexes," in United States. Bureau of the Census. "June 1976," Business Conditions Digest (June 1976) : 52-53. https://fraser.stlouisfed.org/title/43/item/7358/toc/71620 , accessed on March 28, 2024.
United States. Bureau of the Census. "Diffusion Indexes," in United States. Bureau of the Census. "June 1976," Business Conditions Digest (June 1976) : 52-53. https://fraser.stlouisfed.org/title/43/item/7358/toc/71620 , accessed on March 28, 2024.