Columbia subject headings:
Ecology--Philosophy.
Environmentalism--History.
Environmentalism--Political aspects.
Harvard subject headings:
Ecology--Historiography.
Ecology--Political aspects--History.
Human ecology--History
Republics.
Right and left (Political science)
Princeton subject headings:
Ecology--Historiography.
Ecology--Political aspects--History.
Ecology--Social aspects--History.
Republics.
Right and left (Political science)