Scherr, S. J. (1999). Soil degradation: A threat to developing-country food security by 2020? International Food Policy Research Institute.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रScherr, Sara J. Soil Degradation: A Threat to Developing-country Food Security by 2020? Washington, D.C: International Food Policy Research Institute, 1999.
एमएलए (9वां संस्करण) प्रशस्ति पत्रScherr, Sara J. Soil Degradation: A Threat to Developing-country Food Security by 2020? International Food Policy Research Institute, 1999.
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