Columbia subject headings:
Education, Urban--United States--History--19th century.
Education, Urban--United States--History--20th century.
Harvard subject headings:
Education, Urban--United States--History--19th century.
Education, Urban--United States--History--20th century.
Princeton subject headings:
Education, Urban--United States--History--19th century.
Education, Urban--United States--History--20th century.