United States. Bureau of Economic Analysis. "Gross Domestic Product: Fourth Quarter and Annual 2017 (Advance Estimate) : Technical Note, BEA 18-04,"
Bureau of Economic Analysis (BEA) News Releases
(January 26, 2018).
https://fraser.stlouisfed.org/title/6148/item/602611/content/pdf/bea_newsreleases_20180126_technical-note, accessed on May 19, 2025.