United States. Bureau of the Census. "NBER Short List," in United States. Bureau of the Census. "June 1969," Business Conditions Digest (June 1969) : 42-45. https://fraser.stlouisfed.org/title/43/item/7531/toc/242238 , accessed on March 28, 2024.
United States. Bureau of the Census. "NBER Short List," in United States. Bureau of the Census. "June 1969," Business Conditions Digest (June 1969) : 42-45. https://fraser.stlouisfed.org/title/43/item/7531/toc/242238 , accessed on March 28, 2024.