Gaya APA
Betz, Frederick. (1975).
Environmental Geology .
Pennsylvania:
Dowden Hutchinson.
Gaya Chicago
Betz, Frederick.
Environmental Geology.
Pennsylvania:
Dowden Hutchinson,
1975.
Text.
Gaya MLA
Betz, Frederick.
Environmental Geology.
Pennsylvania:
Dowden Hutchinson,
1975.
Text.
Gaya Turabian
Betz, Frederick.
Environmental Geology.
Pennsylvania:
Dowden Hutchinson,
1975.
Print.