Columbia subject headings:
City planning--Congresses.
Municipal water supply--Environmental aspects--Congresses.
Urban ecology (Biology)--Congresses.
Harvard subject headings:
City planning--Congresses
Municipal water supply--Environmental aspects--Congresses.
Urban ecology (Biology)--Congresses.
Princeton subject headings:
City planning--Congresses.
Municipal water supply--Environmental aspects--Congresses.
Urban ecology (Biology)--Congresses.