Columbia subject headings:
Europe--Politics and government--1871-1918.
Russia--Foreign relations.
Soviet Union--Foreign relations.
Harvard subject headings:
Europe--Politics and government--1871-1918.
Russia--Foreign relations--1801-1917.
Soviet Union--Foreign relations--1917-1945.
Soviet Union--Foreign relations.
Princeton subject headings:
Europe--Politics and government--1871-1918.
Soviet Union--Foreign relations.