Não informado. (1958). Lead Abstracts. Lead Development Association.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Lead Abstracts. London: Lead Development Association, 1958.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Lead Abstracts. Lead Development Association, 1958.
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