United States. Bureau of Economic Analysis. "Gross National Product: First Quarter 1991 (Advance) | Corporate Profits: Fourth Quarter 1990 (Revised), BEA 91-15," Bureau of Economic Analysis (BEA) News Releases (April 26, 1991). https://fraser.stlouisfed.org/title/6148/item/596975, accessed on March 28, 2025.