United States. Bureau of Economic Analysis. "U.S. International Investment Position: End of the Fourth Quarter and Year 2015 : Full Release, BEA 16-18," Bureau of Economic Analysis (BEA) News Releases (March 31, 2016). https://fraser.stlouisfed.org/title/6148/item/602337/content/pdf/bea_newsreleases_20160331, accessed on March 5, 2025.