United States. Bureau of Economic Analysis. "Gross Domestic Product: First Quarter 2013 (Second Estimate) | Corporate Profits: First Quarter 2013 (Preliminary Estimate), BEA 13-21," Bureau of Economic Analysis (BEA) News Releases (May 30, 2013). https://fraser.stlouisfed.org/title/6148/item/601545, accessed on March 26, 2025.