United States. Bureau of the Census. "Leading Indicators," in United States. Bureau of the Census. "May 1972," Business Conditions Digest (May 1972) : 69-69. https://fraser.stlouisfed.org/title/43/item/7566/toc/88821 , accessed on April 23, 2024.
United States. Bureau of the Census. "Leading Indicators," in United States. Bureau of the Census. "May 1972," Business Conditions Digest (May 1972) : 69-69. https://fraser.stlouisfed.org/title/43/item/7566/toc/88821 , accessed on April 23, 2024.