Columbia subject headings:
Harvard subject headings:
Hydrology--Research--Congresses.
Hydrology--Study and teaching--Congresses.
International Hydrological Programme. Intergovernmental Council--Congresses.
Water resources development--Congresses
Princeton subject headings:
Hydrology--Research--Congresses.
Hydrology--Study and teaching--Congresses.
International Hydrological Programme. Intergovernmental Council--Congresses.
Water resources development--Congresses.