Columbia subject headings:
Middle class--Europe--History.
Middle class--Europe--Social conditions.
Migration, Internal--Europe--History.
Harvard subject headings:
Middle class--Europe--History.
Middle class--Europe--Social conditions.
Middle class--Europe.
Migration, Internal--Europe--History.
Princeton subject headings:
Middle class--Europe--History.
Middle class--Europe--Social conditions.
Migration, Internal--Europe--History.