Columbia subject headings:
Education, Secondary--Germany--Prussia--History--19th century.
Education, Secondary--Germany--Rhine Province--History--19th century.
Education, Secondary--Germany--Westphalia--History--19th century.
Harvard subject headings:
Education, Secondary--Germany--Prussia--History--19th century.
Education, Secondary--Germany--Rhine Province--History--19th century.
Education, Secondary--Germany--Westphalia--History--19th century.
Princeton subject headings:
Education, Secondary--Germany (West)--Rhine Province--History--19th century.
Education, Secondary--Germany (West)--Westphalia--History--19th century.
Education, Secondary--Prussia (Germany)--History--19th century.