Não informado. (1977). Health and Hygiene. Royal Institute of Public Health and Hygiene.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Health and Hygiene. London: Royal Institute of Public Health and Hygiene, 1977.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Health and Hygiene. Royal Institute of Public Health and Hygiene, 1977.
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