Columbia subject headings:
Acheulian culture--Chad Basin.
Chad Basin--Antiquities.
Excavations (Archaeology)--Chad Basin.
Paleolithic period--Chad Basin.
Harvard subject headings:
Acheulian culture--Chad Basin.
Chad Basin--Antiquities.
Excavations (Archaeology)--Chad Basin.
Paleolithic period--Chad Basin.
Princeton subject headings:
Chad--Antiquities.
Paleolithic period--Chad.