Columbia subject headings:
Germany--History--1789-1900--Congresses.
Germany--History--20th century--Congresses.
Revolutions.
Harvard subject headings:
Germany--History--1789-1900--Congresses.
Germany--History--20th century--Congresses.
Revolutions
Princeton subject headings:
Germany--History--1789-1900--Congresses.
Germany--History--20th century--Congresses.
Revolutions.