United States. Department of Commerce and United States. Bureau of Economic Analysis. "Revised First Quarter 1978," The National Income and Product Account (1978-05-01). https://fraser.stlouisfed.org/title/52/item/57018, accessed on July 29, 2021.
United States. Department of Commerce and United States. Bureau of Economic Analysis. "Revised First Quarter 1978," The National Income and Product Account (1978-05-01). https://fraser.stlouisfed.org/title/52/item/57018, accessed on July 29, 2021.