Não informado. (1935). Soil conservation. U.S. Department of Agriculture, Soil Conservation Service.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Soil Conservation. Washington: U.S. Department of Agriculture, Soil Conservation Service, 1935.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Soil Conservation. U.S. Department of Agriculture, Soil Conservation Service, 1935.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.