United States. Bureau of the Census. "Method of Presentation," in United States. Bureau of the Census. "May 1969," Business Conditions Digest (May 1969) : 7-10. https://fraser.stlouisfed.org/title/43/item/7530/toc/303343 , accessed on May 3, 2024.
United States. Bureau of the Census. "Method of Presentation," in United States. Bureau of the Census. "May 1969," Business Conditions Digest (May 1969) : 7-10. https://fraser.stlouisfed.org/title/43/item/7530/toc/303343 , accessed on May 3, 2024.