Columbia subject headings:
Buildings--Italy--Ostia.
Buildings--Italy--Rome.
Ostia (Italy)--Antiquities.
Rome (Italy)--Antiquities.
Harvard subject headings:
Archaeological dating--Italy--Ostia (Extinct city)
Archaeological dating--Italy--Rome.
Architecture, Roman--Italy--Ostia (Extinct city)
Architecture, Roman--Italy--Rome.
Princeton subject headings:
Architecture, Roman.
Ostia (Extinct city)
Ostia (Extinct city)--Buildings, structures, etc.
Rome (Italy)--Antiquities.
Rome (Italy)--Buildings, structures, etc.