World Health Organization. (1999). Sexually transmitted infections prevalence study methodology. World Health Organization.
Chicago Style aipamenaWorld Health Organization. Sexually Transmitted Infections Prevalence Study Methodology. Geneva,Switzerland: World Health Organization, 1999.
MLA aipamenaWorld Health Organization. Sexually Transmitted Infections Prevalence Study Methodology. World Health Organization, 1999.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.