Columbia subject headings:
Educational sociology--Germany--Duisburg--History--19th century.
Educational sociology--Germany--Minden (Landkreis)--History--19th century.
Social mobility--Germany--Duisburg--History--19th century.
Social mobility--Germany--Minden (Landkreis)--History--19th century.
Students--Germany--Duisburg--Social conditions.
Students--Germany--Minden (Landkreis)--Social conditions.
Harvard subject headings:
Educational sociology--Germany--Duisburg--History--19th century.
Educational sociology--Germany--Minden--History--19th century.
Social mobility--Germany--Duisburg--History--19th century.
Social mobility--Germany--Minden--History--19th century.
Students--Germany--Duisburg--Social conditions.
Students--Germany--Minden--Social conditions.
Princeton subject headings:
Education, Urban--Germany--History--19th century.
Educational sociology--Germany--History--19th century.
Social mobility--Germany--History--19th century.