World Health Organization. (1999). Sexually transmitted infections prevalence study methodology. World Health Organization.
Chicago-referens (17:e uppl.)World Health Organization. Sexually Transmitted Infections Prevalence Study Methodology. Geneva,Switzerland: World Health Organization, 1999.
MLA-referens (8:e uppl.)World Health Organization. Sexually Transmitted Infections Prevalence Study Methodology. World Health Organization, 1999.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.