Columbia subject headings:
Harvard subject headings:
Balkan Peninsula--Foreign relations--Poland--Sources.
Balkan Peninsula--Politics and government--20th century--Sources.
Danube River Region--Foreign relations--20th century--Sources.
Europe--Politics and government--1918-1945--Sources.
Poland--Foreign relations--20th century--Sources.
Poland--Foreign relations--Balkan Peninsula--Sources.
Poland. Ministerstwo Spraw Zagranicznych--Sources.
Princeton subject headings:
Balkan Peninsula--Foreign relations--Poland--Sources.
Balkan Peninsula--Politics and government--20th century--Sources.
Danube River Region--Foreign relations--20th century--Sources.
Europe--Politics and government--1918-1945--Sources.
Poland--Foreign relations--20th century--Sources.
Poland--Foreign relations--Balkan Peninsula--Sources.
Poland. Ministerstwo Spraw Zagranicznych--Sources.