Columbia subject headings:
Harvard subject headings:
Duero River Valley (Spain and Portugal)--Antiquities, Roman.
Extinct cities--Duero River Valley (Spain and Portugal)
Roads, Roman--Duero River Valley (Spain and Portugal)
Romans--Duero River Valley (Spain and Portugal)
Spain--Antiquities, Roman.
Princeton subject headings:
Duero River Valley (Spain and Portugal)--Antiquities, Roman.
Extinct cities--Duero River Valley (Spain and Portugal).
Roads, Roman--Duero River Valley (Spain and Portugal).
Romans--Duero River Valley (Spain and Portugal).
Spain--Antiquities, Roman.