United States. Bureau of Economic Analysis. "Gross National Product : Preliminary Fourth Quarter and 1968 Annual Totals, OBE 69-2,"
Bureau of Economic Analysis (BEA) News Releases
(January 14, 1969).
https://fraser.stlouisfed.org/title/6148/item/594964, accessed on March 22, 2025.
@FedFRASER