APA (7e ed.) Bronvermelding

Graaff, J. d. (1996). The price of soil erosion: An economic evaluation of soil conservation and watershed development. Wageningen Agricultural University.

Chicago (17e ed.) Bronvermelding

Graaff, J. de. The Price of Soil Erosion: An Economic Evaluation of Soil Conservation and Watershed Development. Wageningen, Netherlands: Wageningen Agricultural University, 1996.

MLA (8e ed.) Bronvermelding

Graaff, J. de. The Price of Soil Erosion: An Economic Evaluation of Soil Conservation and Watershed Development. Wageningen Agricultural University, 1996.