Spaan, W. P. (1979). Course instruction: Soil conservation and erosion control. Wageningen: Wageningen Agricultural Univ.
Citación estilo ChicagoSpaan, W. P. Course Instruction: Soil Conservation and Erosion Control. Wageningen: Wageningen Agricultural Univ, 1979.
Cita MLASpaan, W. P. Course Instruction: Soil Conservation and Erosion Control. Wageningen: Wageningen Agricultural Univ, 1979.
Cảnh báo: Các trích dẫn này có thể không phải lúc nào cũng chính xác 100%.