Gaya APA

Crosson, P, R., Stout, A, T. (1983). Productivity Effects of Cropland Erosion in the United States . Amerika: United states of Amerika.

Gaya MLA

Crosson, Pierre, R.., Stout, Anthony, T.. "Productivity Effects of Cropland Erosion in the United States". Amerika: United states of Amerika, 1983. Text.