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2. Centers for Disease Control and Prevention (CDC) 2007 HIV/AIDS surveillance report: Cases of HIV infection and AIDS in the United States and dependent areas http://www.cdc.gov/hiv/topics/surveillance/resources/reports/2005report/pdf/2005SurveillanceReport.pdf
3. Central Intelligence Agency 2009 CIA world factbook 2009 (HIV/AIDS adult prevalence rate) https://www.cia.gov/library/publications/the-world-factbook/geos/uk.html
4. HIV testing: State of the art;Sloand;Journal of the American Medical Association,1991