United States. Department of Commerce. "U.S. International Trade in Goods and Services: Annual Revision for 2016, BEA 17-26, CB 17-85, FT-900 (17-04)," United States Department of Commerce News (June 2, 2017). https://fraser.stlouisfed.org/title/6148/item/602497, accessed on June 16, 2026.