Columbia subject headings:
Harvard subject headings:
Aristocracy (Social class)--Germany--History--Congresses.
Human beings--Effect of environment on--Germany--Congresses.
Nobility--Germany--History--Congresses.
Princeton subject headings:
Aristocracy (Social class)--Germany--History--Congresses.
Human beings--Effect of environment on--Germany--Congresses.
Nobility--Germany--History--Congresses.