Não informado. (2001). Bulletin of the World Health Organization. World Health Organization.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Bulletin of the World Health Organization. Geneva, Suíça: World Health Organization, 2001.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Bulletin of the World Health Organization. World Health Organization, 2001.
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