United States. Bureau of the Census. "Cover Page," in United States. Bureau of the Census. "April 1972," Business Conditions Digest (April 1972) : 1-1. https://fraser.stlouisfed.org/title/43/item/7565/toc/54897 , accessed on April 28, 2024.
United States. Bureau of the Census. "Cover Page," in United States. Bureau of the Census. "April 1972," Business Conditions Digest (April 1972) : 1-1. https://fraser.stlouisfed.org/title/43/item/7565/toc/54897 , accessed on April 28, 2024.