United States. Bureau of Economic Analysis. "U.S. International Trade in Goods and Services: Annual Revision : Full Release, BEA 20-26, CB 20-82," Bureau of Economic Analysis (BEA) News Releases (June 4, 2020). https://fraser.stlouisfed.org/title/6148/item/602901/content/pdf/bea_newsreleases_20200604_b, accessed on March 17, 2025.