United States. Department of Commerce. "U.S. International Trade in Goods and Services, September 2012, BEA 12-50, CB 12-211, FT-900 (12-09),"
United States Department of Commerce News
(November 8, 2012).
https://fraser.stlouisfed.org/title/6148/item/601363, accessed on May 30, 2026.