Cita APA (7th ed.)
Kohnke Helmut. (1968). Soil physics. Tata Mc Graw Hill.
Cita Chicago (17th ed.)
Kohnke Helmut. Soil Physics. New Delhi: Tata Mc Graw Hill, 1968.
Cita MLA (9th ed.)
Kohnke Helmut. Soil Physics. Tata Mc Graw Hill, 1968.
Atenció: Aquestes cites poden no estar 100% correctes.