Columbia subject headings:
Eutrophication--Congresses.
Freshwater biology--Congresses.
Water--Pollution--Congresses.
Harvard subject headings:
Eutrophication--Congresses.
Freshwater biology--Congresses.
Limnology--Congresses.
Water--Pollution--Congresses
Princeton subject headings:
Eutrophication--Congresses.
Freshwater biology--Congresses.
Water--Pollution--Congresses.