Columbia subject headings:
Harvard subject headings:
Germans--Poland--History--19th century--Congresses.
Germans--Poland--History--20th century--Congresses.
Poland--History--19th century--Congresses.
Poland--History--20th century--Congresses.
Princeton subject headings:
Germans--Poland--Congresses.
Immigrants--Poland--Congresses.
Poland--Emigration and immigration--Congresses.