United States. Bureau of the Census. "March 1981," Business Conditions Digest (March 1981). https://fraser.stlouisfed.org/title/43/item/7415, accessed on July 14, 2024.
United States. Bureau of the Census. "March 1981," Business Conditions Digest (March 1981). https://fraser.stlouisfed.org/title/43/item/7415, accessed on July 14, 2024.