Columbia subject headings:
Cities and towns--United States--History--20th century.
Urbanization--United States--History--20th century.
Harvard subject headings:
Cities and towns--United States--History--20th century.
Urbanization--United States--History--20th century.
Princeton subject headings:
Cities and towns--United States--History--20th century.
Urbanization--United States--History--20th century.