Columbia subject headings:
Europe--Foreign relations--1871-1918--Sources--Bibliography.
Europe--Foreign relations--1918-1945--Sources--Bibliography.
Harvard subject headings:
Europe--Foreign relations--1871-1918--Sources--Bibliography.
Europe--Foreign relations--1918-1945--Sources--Bibliography.
Princeton subject headings:
Europe--Foreign relations--1871-1918--Sources--Bibliography.
Europe--Foreign relations--1918-1945--Sources--Bibliography.