Columbia subject headings:
Harvard subject headings:
Architecture--Italy--Siena--Guidebooks.
Art, Italian--Italy--Siena--Guidebooks.
Art--Italy--Siena--Guidebooks.
Siena (Italy)--Buildings, structures, etc.--Guidebooks.
Siena (Italy)--Guidebooks.
Princeton subject headings:
Architecture--Italy--Siena.
Art--Italy--Siena.
Siena (Italy)--Guidebooks.
Siena (Italy)--History.