APA

Gustafson A. F., . (1937). Conservation of the soil. New York: McGraw-Hill.

Chicago

Gustafson A F, . 1937. Conservation of the soil. New York: McGraw-Hill.

Harvard

Gustafson A. F., . (1937). Conservation of the soil. New York: McGraw-Hill.

MLA

Gustafson A F, . Conservation of the soil. New York: McGraw-Hill. 1937.