Columbia subject headings:
Generations--Great Britain--History--Congresses.
Generations--Netherlands--History--Congresses.
Social evolution--Congresses.
Working class--Great Britain--History--Congresses.
Working class--Netherlands--History--Congresses.
Harvard subject headings:
Working class--Europe--History--Congresses.
Princeton subject headings:
Generations--Great Britain--History--Congresses.
Generations--Netherlands--History--Congresses.
Social evolution--Congresses.
Working class--Great Britain--History--Congresses.
Working class--Netherlands--History--Congresses.