Columbia subject headings:
Immigrants--History--20th century.
Immigrants--History--21st century.
Refugees--History--20th century.
Refugees--History--21st century.
Harvard subject headings:
Immigrants--History--20th century.
Immigrants--History--21st century.
Refugees--History--20th century.
Refugees--History--21st century.
Princeton subject headings:
Immigrants--History--20th century.
Immigrants--History--21st century.
Refugees--History--20th century.
Refugees--History--21st century.