Não informado. (1951). Annual Report of the International Tin Research Council. International Tin Research Institute.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Annual Report of the International Tin Research Council. Greenford, Inglaterra: International Tin Research Institute, 1951.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Annual Report of the International Tin Research Council. International Tin Research Institute, 1951.
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