Columbia subject headings:
Harvard subject headings:
Lippe (Germany : Kreis)--Emigration and immigration--Congresses.
Lippe (Germany : Kreis)--Social conditions--Congresses.
Migrant labor--Germany--Lippe (Kreis)--History--Congresses.
Seasonal labor--Germany--Lippe (Kreis)--History--Congresses.
Princeton subject headings:
Lippe (Germany : Kreis)--Emigration and immigration--Congresses.
Lippe (Germany : Kreis)--Social conditions--Congresses.
Migrant labor--Germany--Lippe (Kreis)--History--Congresses.
Seasonal labor--Germany--Lippe (Kreis)--History--Congresses.