United States. Department of Commerce. "U.S. International Trade in Goods and Services: January 2015, BEA 15-09, CB 15-34, FT-900 (15-01),"
United States Department of Commerce News
(March 6, 2015).
https://fraser.stlouisfed.org/title/6148/item/602227, accessed on May 31, 2026.