United States. Bureau of the Census. "Composite Indexes," in United States. Bureau of the Census. "July 1971," Business Conditions Digest (July 1971) : 40-41. https://fraser.stlouisfed.org/title/43/item/7556/toc/149228 , accessed on May 13, 2024.
United States. Bureau of the Census. "Composite Indexes," in United States. Bureau of the Census. "July 1971," Business Conditions Digest (July 1971) : 40-41. https://fraser.stlouisfed.org/title/43/item/7556/toc/149228 , accessed on May 13, 2024.