Columbia subject headings:
Labor unions--Poland--History.
NSZZ "Solidarność" (Labor organization)--History.
Working class--Poland--History.
Harvard subject headings:
Labor unions--Poland
Labor unions--Poland--History--20th century.
NSZZ "Solidarność" (Labor organization)
Princeton subject headings:
Labor unions--Poland--History--20th century.
NSZZ "Solidarność" (Labor organization)