Columbia subject headings:
Italy--Antiquities--Congresses.
Phlegraean Plain (Italy)--Antiquities--Congresses.
Harvard subject headings:
Excavations (Archaeology)--Italy--Phlegraean Plain--Congresses.
Italy--Antiquities--Congresses.
Phlegraean Plain (Italy)--Antiquities--Congresses.
Princeton subject headings:
Phlegraean Plain (Italy)--History--Congresses.