United States. Bureau of the Census. "Aggregate Series," in United States. Bureau of the Census. "March 1969," Business Conditions Digest (March 1969) : 46-48. https://fraser.stlouisfed.org/title/43/item/7528/toc/62137 , accessed on May 8, 2024.
United States. Bureau of the Census. "Aggregate Series," in United States. Bureau of the Census. "March 1969," Business Conditions Digest (March 1969) : 46-48. https://fraser.stlouisfed.org/title/43/item/7528/toc/62137 , accessed on May 8, 2024.