United States. Bureau of the Census. "Leading Indicators," in United States. Bureau of the Census. "June 1968," Business Conditions Digest (June 1968) : 17-24. https://fraser.stlouisfed.org/title/43/item/7252/toc/428860 , accessed on March 29, 2024.
United States. Bureau of the Census. "Leading Indicators," in United States. Bureau of the Census. "June 1968," Business Conditions Digest (June 1968) : 17-24. https://fraser.stlouisfed.org/title/43/item/7252/toc/428860 , accessed on March 29, 2024.