World Health Organization. (2000). Air quality guidelines for europe (2nd-ed.). World Health Organization.
Chicago Style aipamenaWorld Health Organization. Air Quality Guidelines for Europe. 2nd-ed. Copenhagen: World Health Organization, 2000.
MLA aipamenaWorld Health Organization. Air Quality Guidelines for Europe. 2nd-ed. World Health Organization, 2000.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.