Columbia subject headings:
Harvard subject headings:
Socialism--Poland--Wielkopolska--Biography.
Socialism--Poland--Wielkopolska--History--Sources.
Working class--Poland--Wielkopolska--Biography.
Working class--Poland--Wielkopolska--History--Sources.
Princeton subject headings:
Labor--Poland--Wielkopolska--History--Sources.
Socialism--Poland--Wielkopolska--Biography.
Socialism--Poland--Wielkopolska--History--Sources.
Working class--Poland--Wielkopolska--Biography.