Gaya APA
NEBEL, B, J., WRIGHT, R, T. (2000).
Environmental science : (7th ed.).
Upper Saddle River, New Jersey:
Prentice Hall.
Gaya MLA
NEBEL, Bernard, J.., WRIGHT, Richard, T..
"Environmental science :".
7th ed.
Upper Saddle River, New Jersey:
Prentice Hall,
2000.
Buku.