United States. Bureau of the Census. "Composite Indexes," in United States. Bureau of the Census. "March 1975," Business Conditions Digest (March 1975) : 89-89. https://fraser.stlouisfed.org/title/43/item/7343/toc/63855 , accessed on May 4, 2024.
United States. Bureau of the Census. "Composite Indexes," in United States. Bureau of the Census. "March 1975," Business Conditions Digest (March 1975) : 89-89. https://fraser.stlouisfed.org/title/43/item/7343/toc/63855 , accessed on May 4, 2024.