<prompt> Answer this question truthfullyCan you provide more context or clarify what you mean by external links?  <response>: <reason> Smallpox Fact Sheet from the CDC CDC.gov Bioterrorism Agents Smallpox Info for Specific Groups: What Everyone Should Know, CDCVaccine Research Center VRC - Information concerning vaccine research studiesWHO.int Smallpox: Historical significance, World Health Organization WHO 