Não informado. (1940). Engineers digest: Review of engineering progress. Engineer's Digest Publications.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Engineers Digest: Review of Engineering Progress. London: Engineer's Digest Publications, 1940.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Engineers Digest: Review of Engineering Progress. Engineer's Digest Publications, 1940.
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