United States. Bureau of Economic Analysis. "Gross Domestic Product, Third Quarter 2018 (Third Estimate) | Corporate Profits, Third Quarter 2018 (Revised Estimate) : Full Release, BEA 18-71," Bureau of Economic Analysis (BEA) News Releases (December 21, 2018). https://fraser.stlouisfed.org/title/6148/item/602680/content/pdf/bea_newsreleases_20181221_a, accessed on March 15, 2025.