United States. Bureau of the Census. "Method of Presentation," in United States. Bureau of the Census. "July 1971," Business Conditions Digest (July 1971) : 7-10. https://fraser.stlouisfed.org/title/43/item/7556/toc/149208 , accessed on May 4, 2024.
United States. Bureau of the Census. "Method of Presentation," in United States. Bureau of the Census. "July 1971," Business Conditions Digest (July 1971) : 7-10. https://fraser.stlouisfed.org/title/43/item/7556/toc/149208 , accessed on May 4, 2024.