Columbia subject headings:
Harvard subject headings:
Conservationists--Germany--Biography.
Denazification--Germany--History--20th century.
Deutscher Naturschutzring--History--20th century.
Engelhardt, Wolfgang, 1922-
Environmental protection--Germany--History--20th century.
Nature conservation--Germany--History--20th century.
Princeton subject headings:
Conservationists--Germany.
Denazification--Germany.
Engelhardt, Wolfgang, 1922-
Environmentalists--Germany.