Columbia subject headings:
Landscape architecture--Congresses.
Landscape assessment--Congresses.
Nature (Aesthetics)--Congresses.
Harvard subject headings:
Landscape protection.
Landscapes--Conservation and restoration.
Princeton subject headings:
Environmental protection--Spain--Congresses.
Landscape architecture--Spain--Congresses.
Landscape protection--Spain--Congresses.
Landscapes in literature--Congresses.
Spain--Environmental conditions--Congresses.