Columbia subject headings:
Architecture--Conservation and restoration--Congresses.
Buildings--Repair and reconstruction--Congresses.
Historic buildings--Conservation and restoration--Italy--Congresses.
Stone buildings--Italy--Congresses.
Harvard subject headings:
Building stones--Deterioration--Congresses.
Decoration and ornament, Architectural--Conservation and restoration--Congresses.
Stone buildings--Conservation and restoration--Congresses.
Princeton subject headings: