CDC Travel : http://wwwn.cdc.gov/travel/default.aspx Yellow Book 2008 : http://wwwn.cdc.gov/travel/contentYellowBook.aspx contents : http://wwwn.cdc.gov/travel/ybToc.aspx USA YF Vaccine Center : http://www2.ncid.cdc.gov/travel/yellowfever/ USA Travel Clinic : http://wwwn.cdc.gov/travel/contentTravelClinics.aspx