United States. Bureau of Economic Analysis. "U.S. International Trade in Goods and Services: May 2020 : Historical Comparisons, BEA 20-33, CB 20-98," Bureau of Economic Analysis (BEA) News Releases (July 2, 2020). https://fraser.stlouisfed.org/title/6148/item/602908/content/pdf/bea_newsreleases_20200702_historical-comparisons, accessed on March 23, 2025.