Columbia subject headings:
Architecture, Romanesque--Italy--Siena (Province)
Siena (Italy : Province)--Description and travel.
Harvard subject headings:
Architecture, Romanesque--Italy--Siena.
Architecture--Italy--Siena.
Christian art and symbolism--Italy--Siena--Medieval, 500-1500.
Church architecture--Italy--Siena.
Princeton subject headings:
Architecture, Romanesque--Italy--Siena (Province).