Columbia subject headings:
Ecology--Philosophy.
Hösle, Vittorio, 1960-
Jonas, Hans, 1903-1993.
Picht, Georg, 1913-1982.
Harvard subject headings:
Ecology--Philosophy
Environmental ethics--History--20th century.
Human ecology--History--20th century.
Hösle, Vittorio, 196.
Hösle, Vittorio, 1960-
Jonas, Hans, 1903-1993.
Picht, Georg, 1913-1982
Princeton subject headings:
Environmental ethics--History--20th century.
Hösle, Vittorio, 1960-
Human ecology--History--20th century.
Jonas, Hans, 1903-1993.
Picht, Georg, 1913-