Columbia subject headings:
Architecture, Medieval--Conservation and restoration--Europe--Congresses.
Cathedrals--Conservation and restoration--Europe--Congresses.
Cathedrals--Conservation and restoration--Spain--Congresses.
Harvard subject headings:
Princeton subject headings:
Architecture, Medieval--Conservation and restoration--Europe--Congresses.
Cathedrals--Conservation and restoration--Europe--Congresses.
Cathedrals--Conservation and restoration--Spain--Congresses.