United States. Bureau of Economic Analysis. "U.S. International Trade in Goods and Services: February 2018 : Full Release, BEA 18-17, CB 18-52," Bureau of Economic Analysis (BEA) News Releases (April 5, 2018). https://fraser.stlouisfed.org/title/6148/item/602624/content/pdf/bea_newsreleases_20180405, accessed on March 6, 2025.