United States. Bureau of Economic Analysis. "Gross Domestic Product (Third Estimate), Corporate Profits (Revised Estimate), and GDP by Industry, First Quarter 2021, BEA 21-29,"
Bureau of Economic Analysis (BEA) News Releases
(June 24, 2021).
https://fraser.stlouisfed.org/title/6148/item/604396, accessed on July 14, 2025.