United States. Bureau of the Census. "Title Page," in United States. Bureau of the Census. "January 1968," Business Conditions Digest (January 1968) : 2-2. https://fraser.stlouisfed.org/title/43/item/7247/toc/394246 , accessed on June 23, 2024.
United States. Bureau of the Census. "Title Page," in United States. Bureau of the Census. "January 1968," Business Conditions Digest (January 1968) : 2-2. https://fraser.stlouisfed.org/title/43/item/7247/toc/394246 , accessed on June 23, 2024.