Columbia subject headings:
Collective labor agreements--Europe--History--20th century.
Europe--Emigration and immigration--History--20th century.
Foreign workers--Europe--History--20th century.
Labor market--Europe--History--20th century.
Labor mobility--Europe--History--20th century.
Trade regulation--Europe--History--20th century.
Harvard subject headings:
Collective labor agreements--Europe--History--20th century.
Europe--Emigration and immigration--History--20th century.
Foreign workers--Europe--History--20th century.
Labor market--Europe--History--20th century.
Labor mobility--Europe--History--20th century.
Trade regulation--Europe--History--20th century.
Princeton subject headings:
Collective labor agreements--Europe--History--20th century.
Europe--Emigration and immigration--History--20th century.
Foreign workers--Europe--History--20th century.
Labor market--Europe--History--20th century.
Labor mobility--Europe--History--20th century.
Trade regulations--Europe--History--20th century.