United States. Bureau of the Census. "Table of Contents," in United States. Bureau of the Census. "June 1971," Business Conditions Digest (June 1971) : 3-4. https://fraser.stlouisfed.org/title/43/item/7555/toc/237449 , accessed on May 11, 2024.
United States. Bureau of the Census. "Table of Contents," in United States. Bureau of the Census. "June 1971," Business Conditions Digest (June 1971) : 3-4. https://fraser.stlouisfed.org/title/43/item/7555/toc/237449 , accessed on May 11, 2024.