United States. Department of Commerce. "Private Services-Producing Sector Continued to Lead Growth in 2006 : Revised Statistics of Gross Domestic Product by Industry, 2004-2006, BEA 08-02," United States Department of Commerce News (January 29, 2008). https://fraser.stlouisfed.org/title/6148/item/600435, accessed on May 31, 2026.