United States. Bureau of the Census. "March 1966," Business Conditions Digest (March 1966). https://fraser.stlouisfed.org/title/43/item/7225, accessed on July 11, 2024.
United States. Bureau of the Census. "March 1966," Business Conditions Digest (March 1966). https://fraser.stlouisfed.org/title/43/item/7225, accessed on July 11, 2024.