United States. Department of Commerce. "National Income and Product Accounts : Gross Domestic Product: Second Quarter 2013 (Advance Estimate) | Comprehensive Revision: 1929 Through First Quarter 2013, BEA 13-34," United States Department of Commerce News (July 31, 2013). https://fraser.stlouisfed.org/title/6148/item/601557, accessed on May 31, 2026.