World Health Organisation. (1989). Health of the elderly World Health organisation. World Health Organisation.
Chicago Style aipamenaWorld Health Organisation. Health of the Elderly World Health Organisation. Geneva: World Health Organisation, 1989.
MLA aipamenaWorld Health Organisation. Health of the Elderly World Health Organisation. World Health Organisation, 1989.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.