United States. Bureau of Economic Analysis. "U.S. International Trade in Goods and Services: August 2013 : Information Section, BEA 13-49, CB 13-174, FT-900 (13-08)," Bureau of Economic Analysis (BEA) News Releases (October 24, 2013). https://fraser.stlouisfed.org/title/6148/item/601572/content/pdf/bea_newsreleases_20131024_information-section, accessed on March 20, 2025.