Columbia subject headings:
Africa, West--Civilization.
Civilization, Ancient.
Social evolution.
Writing--History.
Writing--Social aspects.
Harvard subject headings:
Africa, West--Civilization.
Civilization, Ancient.
Social evolution.
Writing--History
Writing--Social aspects.
Princeton subject headings:
Africa, West--Civilization.
Civilization, Ancient.
Social evolution.
Writing--History.
Writing--Social aspects.