Columbia subject headings:
Europe--Economic conditions--Congresses.
Europe--Social conditions--Congresses.
Social ethics--Congresses.
Social prediction--Europe--Congresses.
Harvard subject headings:
Europe--Economic conditions--Congresses.
Europe--Social conditions--Congresses.
Social ethics--Congresses.
Social prediction--Europe--Congresses.
Princeton subject headings:
Europe--Economic conditions--Congresses.
Europe--Social conditions--Congresses.
Social ethics--Congresses.
Social prediction--Europe--Congresses.