United States. Bureau of the Census. "Table of Contents," in United States. Bureau of the Census. "April 1969," Business Conditions Digest (April 1969) : 3-4. https://fraser.stlouisfed.org/title/43/item/7529/toc/216872 , accessed on May 3, 2024.
United States. Bureau of the Census. "Table of Contents," in United States. Bureau of the Census. "April 1969," Business Conditions Digest (April 1969) : 3-4. https://fraser.stlouisfed.org/title/43/item/7529/toc/216872 , accessed on May 3, 2024.