Spaan, W. P. (1979). Course instruction: Soil conservation and erosion control. Wageningen: Wageningen Agricultural Univ.
Čikaški stil citiranjaSpaan, W. P. Course Instruction: Soil Conservation and Erosion Control. Wageningen: Wageningen Agricultural Univ, 1979.
MLA način citiranjaSpaan, W. P. Course Instruction: Soil Conservation and Erosion Control. Wageningen: Wageningen Agricultural Univ, 1979.
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