Columbia subject headings:
Middle class--Political activity--Germany--History--19th century.
Middle class--Political activity--Germany--History--20th century.
Middle class--Political activity--Switzerland--History--19th century.
Middle class--Political activity--Switzerland--History--20th century.
Harvard subject headings:
Middle class--Germany--Political activity--History--19th century.
Middle class--Germany--Political activity--History--20th century.
Middle class--Switzerland--Political activity--History--19th century.
Middle class--Switzerland--Political activity--History--20th century.
Princeton subject headings:
Middle class--Germany--Political activity--History--19th century.
Middle class--Germany--Political activity--History--20th century.
Middle class--Switzerland--Political activity--History--19th century.
Middle class--Switzerland--Political activity--History--20th century.