Columbia subject headings:
Glass furnaces, Medieval.
Glassware, Medieval--Europe.
Glassware, Medieval--Italy.
Italy--Antiquities.
Harvard subject headings:
Elsa River Valley (Italy)--Antiquities--Congresses.
Excavations (Archaeology)--Italy--Elsa River Valley--Congresses.
Glass manufacture--Italy--Elsa River Valley--History--To 1500--Congresses.
Glassware, Medieval--Italy--Elsa River Valley--Congresses.
Princeton subject headings: