United States. Bureau of the Census. "Title Page," in United States. Bureau of the Census. "April 1970," Business Conditions Digest (April 1970) : 2-2. https://fraser.stlouisfed.org/title/43/item/7541/toc/179536 , accessed on April 18, 2024.
United States. Bureau of the Census. "Title Page," in United States. Bureau of the Census. "April 1970," Business Conditions Digest (April 1970) : 2-2. https://fraser.stlouisfed.org/title/43/item/7541/toc/179536 , accessed on April 18, 2024.