Troeh, F. R., Hobbs, J. A., & Donahue, R. L. (1999). Soil and water conservation: Productivity and environmental protection (3a. ed.). Prentice Hall.
Cita Chicago (17th ed.)Troeh, Frederick R., J. Arthur Hobbs, i Roy L. Donahue. Soil and Water Conservation: Productivity and Environmental Protection. 3a. ed. Upper Saddle River: Prentice Hall, 1999.
Cita MLA (9th ed.)Troeh, Frederick R., et al. Soil and Water Conservation: Productivity and Environmental Protection. 3a. ed. Prentice Hall, 1999.
Atenció: Aquestes cites poden no estar 100% correctes.