Graaff, J. d. (1996). The price of soil erosion: An economic evaluation of soil conservation and watershed development. Wageningen Agricultural University.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रGraaff, J. de. The Price of Soil Erosion: An Economic Evaluation of Soil Conservation and Watershed Development. Wageningen, Netherlands: Wageningen Agricultural University, 1996.
एमएलए (8वां संस्करण) प्रशस्ति पत्रGraaff, J. de. The Price of Soil Erosion: An Economic Evaluation of Soil Conservation and Watershed Development. Wageningen Agricultural University, 1996.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.