Columbia subject headings:
Chad--Antiquities.
Petroglyphs--Chad.
Petroglyphs--Tibesti Mountains.
Prehistoric peoples--Chad.
Prehistoric peoples--Tibesti Mountains.
Tibesti Mountains--Antiquities.
Harvard subject headings:
Chad--Antiquities
Petroglyphs--Chad.
Petroglyphs--Tibesti Mountains.
Prehistoric peoples--Chad.
Prehistoric peoples--Tibesti Mountains.
Tibesti Mountains--Antiquities.
Princeton subject headings:
Chad--Antiquities.
Petroglyphs--Chad.
Petroglyphs--Tibesti Mountains.
Prehistoric peoples--Chad.
Prehistoric peoples--Tibesti Mountains.
Tibesti Mountains--Antiquities.