Columbia subject headings:
Aquaculture--Congresses.
Sewage as fertilizer--Congresses.
Thermal pollution of rivers, lakes, etc.--Congresses.
Harvard subject headings:
Aquaculture--Congresses
Sewage as fertilizer--Congresses.
Thermal pollution of rivers, lakes, etc.--Congresses.
Princeton subject headings:
Aquaculture--Congresses.
Sewage as fertilizer--Congresses.
Thermal pollution of rivers, lakes, etc.--Congresses.