Columbia subject headings:
Harvard subject headings:
Archival resources--Poland.
Labor movement--Germany--History--Archival resources.
Labor unions--Germany--History--Archival resources--Poland.
Labor unions--Germany--History--Archival resources.
Socialism--Germany--Archival resources.
Socialism--Germany--History--Archival resources--Poland.
Working class--Germany--History--Archival resources--Poland.
Princeton subject headings:
Labor movement--Germany--History--Archival resources--Poland.
Labor unions--Germany--History--Archival resources--Poland.
Socialism--Germany--History--Archival resources--Poland.