1. World Tourism Organization. World tourism barometer. Available at: http://www.world-tourism.org/facts/wtb.html. (Accessed 2011 Oct 7).
2. International Trade Administration, Office of Travel and Tourism Industries, US Department of Commerce. United States resident travelers visiting overseas destinations: 2010 outbound. Available at: http://tinet.ita.doc.gov/outreach. (Accessed 2011 Aug 24).
3. Health Problems After Travel to Developing Countries
4. The Burden of Illness in International Travelers
5. THE COMPROMISED TRAVELER