Columbia subject headings:
Harvard subject headings:
Europe, Central--Economic conditions--Congresses.
Europe, Central--Social conditions--Congresses.
Europe, Eastern--Economic conditions--Congresses.
Europe, Eastern--Social conditions--Congresses.
Princeton subject headings:
Europe, Central--Economic conditions--Congresses.
Europe, Central--Social conditions--Congresses.
Europe, Eastern--Economic conditions--Congresses.
Europe, Eastern--Social conditions--Congresses.