United States. Bureau of Economic Analysis. "U.S. International Investment Position, First Quarter 2021, Year 2020, and Annual Update : Highlights (Annual): U.S. International Investment Position, Year 2020, BEA 21-32," Bureau of Economic Analysis (BEA) News Releases (June 30, 2021). https://fraser.stlouisfed.org/title/6148/item/604420/content/pdf/bea_newsreleases_20210630_highlights-annual, accessed on March 25, 2025.