Columbia subject headings:
Fortification, Greek--Congresses.
Harvard subject headings:
Excavations (Archaeology)--Greece--Congresses.
Excavations (Archaeology)--Mediterranean Region--Congresses
Fortification--Greece--Congresses.
Fortification--Mediterranean Region--Congresses.
Greece--Antiquities--Congresses.
Mediterranean Region--Antiquities--Congresses.
Princeton subject headings:
Fortification, Greek--Congresses.