Columbia subject headings:
Harvard subject headings:
Equality--Germany--History--20th century--Congresses.
Nature and nurture--Germany--History--20th century--Congresses.
Sociobiology--Germany--History--20th century--Congresses.
Princeton subject headings:
Equality--Germany--History--20th century--Congresses.
Nature and nurture--Germany--History--20th century--Congresses.
Sociobiology--Germany--History--20th century--Congresses.