United States. Bureau of the Census. "Cover Page," in United States. Bureau of the Census. "July 1968," Business Conditions Digest (July 1968) : 1-1. https://fraser.stlouisfed.org/title/43/item/7253/toc/409147 , accessed on May 4, 2024.
United States. Bureau of the Census. "Cover Page," in United States. Bureau of the Census. "July 1968," Business Conditions Digest (July 1968) : 1-1. https://fraser.stlouisfed.org/title/43/item/7253/toc/409147 , accessed on May 4, 2024.