United States. Bureau of Economic Analysis. "December 1967," Survey of Current Business (December 1967). https://fraser.stlouisfed.org/title/46/item/9748, accessed on June 21, 2024.
United States. Bureau of Economic Analysis. "December 1967," Survey of Current Business (December 1967). https://fraser.stlouisfed.org/title/46/item/9748, accessed on June 21, 2024.