Columbia subject headings:
Harvard subject headings:
City children--Germany--History--20th century--Congresses.
Social classes--Germany--History--20th century--Congresses.
Urban health--Germany--History--20th century--Congresses.
Urbanization--Germany--History--20th century--Congresses.
Princeton subject headings:
City children--Germany--History--20th century.
City children--Social conditions--20th century.
Sociology, Urban--Germany--History--20th century.