United States. Bureau of the Census. "Cover Page," in United States. Bureau of the Census. "December 1969," Business Conditions Digest (December 1969) : 1-1. https://fraser.stlouisfed.org/title/43/item/7537/toc/83529 , accessed on May 4, 2024.
United States. Bureau of the Census. "Cover Page," in United States. Bureau of the Census. "December 1969," Business Conditions Digest (December 1969) : 1-1. https://fraser.stlouisfed.org/title/43/item/7537/toc/83529 , accessed on May 4, 2024.