Columbia subject headings:
Europe--Economic conditions--Congresses.
Europe--Social conditions--Congresses.
Harvard subject headings:
Europe--Economic conditions--Congresses.
Europe--Social conditions--17th century--Congresses.
Europe--Social conditions--18th century--Congresses.
Europe--Social conditions--Congresses.
Princeton subject headings:
Europe--Economic conditions--Congresses.
Europe--Social conditions--Congresses.