United States. Bureau of Economic Analysis. "Gross Domestic Product: Second Quarter 2018 (Third Estimate) | Corporate Profits: Second Quarter 2018 (Revised Estimate) : Full Release, BEA 18-51," Bureau of Economic Analysis (BEA) News Releases (September 27, 2018). https://fraser.stlouisfed.org/title/6148/item/602659/content/pdf/bea_newsreleases_20180927, accessed on May 16, 2025.