Columbia subject headings:
Architecture, Medieval--Conservation and restoration--Italy--Palermo.
Architecture, Norman--Conservation and restoration--Italy--Palermo.
Church architecture--Conservation and restoration--Italy--Palermo.
Church architecture--Expertising--Italy--Palermo.
Harvard subject headings:
Architecture, Norman--Italy--Palermo--Conservation and restoration.
Church architecture--Italy--Palermo--Conservation and restoration.
Princeton subject headings:
Art, Norman--Italy--Palermo--Conservation and restoration.