Não informado. (1945). Down to earth: A review of agricultural chemical progress. Down Chemical, Agricultural Products Department.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Down to Earth: A Review of Agricultural Chemical Progress. Midland, Mich: Down Chemical, Agricultural Products Department, 1945.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Down to Earth: A Review of Agricultural Chemical Progress. Down Chemical, Agricultural Products Department, 1945.
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