United States. Bureau of Economic Analysis. "Real Direct Tourism Output Grew 2.3 Percent In First Quarter 2007 : Full Release, BEA 07-28," Bureau of Economic Analysis (BEA) News Releases (June 20, 2007). https://fraser.stlouisfed.org/title/6148/item/598969/content/pdf/bea_newsreleases_20070620_release, accessed on June 12, 2025.