Columbia subject headings:
Geomorphology--France--Lorraine.
Geomorphology--Germany--Saarland.
Geomorphology--Luxembourg.
Harvard subject headings:
Geomorphology--France--Lorraine.
Geomorphology--Germany--Saarland.
Geomorphology--Luxembourg.
Princeton subject headings:
Geomorphology--France--Lorraine.
Geomorphology--Germany--Saarland.
Geomorphology--Luxembourg.