APA Style
National Geographic : Angkor, Why an Ancient Civilization Collapsed. (2009).
Washington, D.C:
National Geographic.
Chicago Style
National Geographic : Angkor, Why an Ancient Civilization Collapsed.
.
Washington, D.C:
National Geographic,
2009.
Text.
MLA Style
National Geographic : Angkor, Why an Ancient Civilization Collapsed.
.
Washington, D.C:
National Geographic,
2009.
Text.
Turabian Style
National Geographic : Angkor, Why an Ancient Civilization Collapsed.
Washington, D.C:
National Geographic,
2009.
Print.