United States. Department of Commerce and United States. Bureau of Economic Analysis. "Revised Second Quarter 1990," The National Income and Product Account (1990-08-01). https://fraser.stlouisfed.org/title/52/item/57243, accessed on July 30, 2021.
United States. Department of Commerce and United States. Bureau of Economic Analysis. "Revised Second Quarter 1990," The National Income and Product Account (1990-08-01). https://fraser.stlouisfed.org/title/52/item/57243, accessed on July 30, 2021.