Columbia subject headings:
Harvard subject headings:
Cities and towns
City and town life--Germany--Frankfurt am Main--History.
City and town life--Pennsylvania--Philadelphia--History.
Frankfurt am Main (Germany)
Frankfurt am Main (Germany)--History--20th century.
Frankfurt am Main (Germany)--Social conditions--20th century.
Philadelphia (Pa.)
Philadelphia (Pa.)--History--20th century.
Philadelphia (Pa.)--Social conditions--20th century.
Princeton subject headings:
City and town life--Germany--Frankfurt am Main--History.
City and town life--Pennsylvania--Philadelphia--History.
Frankfurt am Main (Germany)--Social conditions--20th century.
Philadelphia (Pa.)--Social conditions--20th century.