United States. Department of Commerce. "U.S. International Trade in Goods and Services, March 2012, BEA 12-19, CB 12-82, FT-900 (12-03),"
United States Department of Commerce News
(May 10, 2012).
https://fraser.stlouisfed.org/title/6148/item/601333, accessed on May 30, 2026.