APA
Troeh F. R., . (2004). Soil and Water Conservation. : Prentice Hall.
Chicago
Troeh Frederick R, . 2004. Soil and Water Conservation. : Prentice Hall.
Harvard
Troeh F. R., . (2004). Soil and Water Conservation. : Prentice Hall.
MLA
Troeh Frederick R, . Soil and Water Conservation. : Prentice Hall. 2004.