National Institutes of Health (NIH), National Institute of Allergy and Infectious Diseases (NIAID) (May 1, 2000). "HIV Vaccine Glossary". NIAID Fact Sheet. AIDSinfo. Archived from the original on July 16, 2011. Retrieved 2009-08-10.
National Institutes of Health (NIH), National Institute of Allergy and Infectious Diseases (NIAID) (May 1, 2000). "HIV Vaccine Glossary". NIAID Fact Sheet. AIDSinfo. Archived from the original on July 16, 2011. Retrieved 2009-08-10.