Columbia subject headings:
Europe--Foreign relations--1871-1918--Public opinion--Congresses.
Europe--Foreign relations--20th century--Public opinion--Congresses.
Public opinion--Europe--History--19th century--Congresses.
Public opinion--Europe--History--20th century--Congresses.
Harvard subject headings:
Europe--Foreign relations--1871-1918--Public opinion--Congresses.
Europe--Foreign relations--1918-1945--Public opinion--Congresses.
Europe--Foreign relations--1945---Public opinion--Congresses.
Public opinion--Europe--History--19th century--Congresses.
Public opinion--Europe--History--20th century--Congresses.
Princeton subject headings:
Political science--Congresses.
Public opinion--Congresses.
World politics--Congresses.