Columbia subject headings:
Asylum, Right of--Europe--History--20th century--Congresses.
Asylum, Right of--History--20th century--Congresses.
Emigration and immigration--History--20th century--Congresses.
Europe--Emigration and immigration--History--20th century--Congresses.
Refugees--Europe--History--20th century--Congresses.
Refugees--History--20th century--Congresses.
Harvard subject headings:
Asylum, Right of--Europe--History--20th century--Congresses.
Asylum, Right of--History--20th century--Congresses.
Emigration and immigration--History--20th century--Congresses.
Europe--Emigration and immigration--History--20th century--Congresses.
Refugees--Europe--History--20th century--Congresses.
Refugees--History--20th century--Congresses.
Princeton subject headings:
Asylum, Right of--Europe--History--20th century--Congresses.
Asylum, Right of--History--20th century--Congresses.
Emigration and immigration--History--20th century--Congresses.
Europe--Emigration and immigration--History--20th century--Congresses.
Refugees--Europe--History--20th century--Congresses.
Refugees--History--20th century--Congresses.