United States. Bureau of Economic Analysis. "National Income and Product Accounts : Gross Domestic Product: Second Quarter 2009 (Advance Estimate)|Comprehensive Revision: 1929 Through First Quarter 2009, BEA 09-33,"
Bureau of Economic Analysis (BEA) News Releases
(July 31, 2009).
https://fraser.stlouisfed.org/title/6148/item/600682, accessed on June 18, 2025.