Gaya APA
Childs, O, E. (1963).
Backbone of The Americas : Tectonic History from Pole to Pole .
WISCONSIN:
The Collegiate Press.
Gaya MLA
Childs, Orlo, E..
"Backbone of The Americas : Tectonic History from Pole to Pole".
WISCONSIN:
The Collegiate Press,
1963.
Text.