Columbia subject headings:
Cultural property--Protection--Congresses.
Historic sites--Conservation and restoration.
Tourism and the arts--Congresses.
Tourism--Europe--Congresses.
Tourism--Switzerland--Congresses.
Harvard subject headings:
Cultural property--Protection--Congresses
Historic sites--Conservation and restoration--Congresses.
Tourism and the arts--Congresses.
Tourism--Environmental aspects--Alps--Congresses.
Princeton subject headings: