Columbia subject headings:
Architecture, Medieval--Italy--Congresses.
Architecture, Medieval--Italy--Siena (Province)--Congresses.
Castles--Italy--Congresses.
Castles--Italy--Siena (Province)--Congresses.
Excavations (Archaeology)--Italy--Congresses.
Harvard subject headings:
Architecture, Medieval--Italy--Congresses.
Architecture, Medieval--Italy--Siena (Province)--Congresses.
Castles--Italy--Congresses.
Castles--Italy--Siena (Province)--Congresses.
Excavations (Archaeology)--Italy--Congresses
Montarrenti (Italy)--Antiquities--Congresses.
Princeton subject headings:
Architecture, Medieval--Italy--Congresses.
Architecture, Medieval--Italy--Siena (Province)--Congresses.
Castles--Italy--Congresses.
Castles--Italy--Siena (Province)--Congresses.
Excavations (Archaeology)--Italy--Congresses.