Não informado. (1981). Abstracts on hygiene and communicable diseases. Bureau of Hygiene and Tropical Diseases.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Abstracts on Hygiene and Communicable Diseases. London: Bureau of Hygiene and Tropical Diseases, 1981.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Abstracts on Hygiene and Communicable Diseases. Bureau of Hygiene and Tropical Diseases, 1981.
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