Gaya APA
TROEH, F, R, H, J, A, D, R, L. (2004).
Soil and water conservation for productivity and environmental protection. Fourth edition .
:
Pearson education. Prentice Hall.
Gaya MLA
TROEH, Frederick, R,;, HOBB,, J., Athur;, DONAHUE,, Roy, L..
"Soil and water conservation for productivity and environmental protection. Fourth edition".
:
Pearson education. Prentice Hall,
2004.
Buku.