Columbia subject headings:
Economic development--Europe--History.
Europe--Economic conditions.
Europe--Social conditions--History.
Social change--Europe--History.
Harvard subject headings:
Europe--Economic conditions--Congresses.
Europe--Social conditions--Congresses.
Germany--Economic conditions--Congresses.
Germany--Social conditions--Congresses.
Princeton subject headings:
Europe--Economic conditions--Congresses.
Europe--Social conditions--Congresses.
Germany--Economic conditions--Congresses.
Germany--Social conditions--Congresses.