Columbia subject headings:
Harvard subject headings:
Environmental policy--International cooperation
Water--Pollution--Elbe River (Czech Republic and Germany)--History.
Water--Pollution--Government policy.
Water--Pollution--Rhine River--History.
Princeton subject headings:
Environmental policy--International cooperation.
Water--Pollution--Elbe River (Czech Republic and Germany)--History.
Water--Pollution--Government policy.
Water--Pollution--Rhine River--History.