Cita APA (7a ed.)

Keffer, C. A. (1907). Nature studies on the farm: Soils and plants. American Book Co..

Cita Chicago Style (17a ed.)

Keffer, Charles A. Nature Studies on the Farm: Soils and Plants. New York: American Book Co., 1907.

Cita MLA (8a ed.)

Keffer, Charles A. Nature Studies on the Farm: Soils and Plants. American Book Co., 1907.