Columbia subject headings:
Harvard subject headings:
Excavations (Archaeology)--Europe--Congresses
Excavations (Archaeology)--Germany--Spessart--Congresses.
Glass manufacture--Europe--History--Congresses.
Glass manufacture--Germany--Spessart--History--Congresses.
Princeton subject headings:
Glass manufacture--Europe--History--Congresses.
Glassware--Europe--History--Congresses.