Columbia subject headings:
Italy--Antiquities.
Ostia (Italy)--Antiquities.
Ostia (Italy)--Guidebooks.
Harvard subject headings:
Harbors--Italy--Ostia (Extinct city)
Italy--Antiquities.
Ostia (Italy)--Antiquities.
Ostia (Italy)--Guidebooks.
Princeton subject headings:
Excavations (Archaeology)--Italy--Ostia (Extinct city).
Italy--Antiquities, Roman.
Ostia (Extinct city)--Description.