United States. Bureau of the Census. "Diffusion Indexes," in United States. Bureau of the Census. "May 1976," Business Conditions Digest (May 1976) : 103-104. https://fraser.stlouisfed.org/title/43/item/7357/toc/116599 , accessed on April 23, 2024.
United States. Bureau of the Census. "Diffusion Indexes," in United States. Bureau of the Census. "May 1976," Business Conditions Digest (May 1976) : 103-104. https://fraser.stlouisfed.org/title/43/item/7357/toc/116599 , accessed on April 23, 2024.