Columbia subject headings:
Harvard subject headings:
Amazon River Region--Economic conditions--Congresses.
Amazon River Region--Social conditions--Congresses.
Ecology--Amazon River Region--Congresses.
Indians of South America--Amazon River Region--Congresses.
Princeton subject headings:
Amazon River Region--Economic conditions--Congresses.
Amazon River Region--Social conditions--Congresses.
Indians of South America--Amazon River Region--Congresses.
Natural resources--Amazon River Region--Congresses.