Columbia subject headings:
City planning--Italy--Siena--History--To 1500.
Public works--Italy--Siena--History--To 1500.
Siena (Italy)--Politics and government.
Harvard subject headings:
City planning--Italy--Siena--History--To 1500.
Public works--Italy--Siena--History--To 1500.
Siena (Italy)--Politics and government.
Princeton subject headings:
City planning--Italy--Siena.
Siena (Italy)--Buildings, structures, etc.
Siena (Italy)--History.