Columbia subject headings:
Harvard subject headings:
Drainage--Germany--Hamburg--History--20th century.
Germany--History--1933-1945.
National socialism--Germany--Hamburg.
Runoff--Germany--Hamburg--History--20th century.
Water-supply--Germany--Hamburg--History--20th century.
Waterworks--Germany--Hamburg--History--20th century.
Princeton subject headings:
Drainage--Germany--Hamburg--History--20th century.
Germany--History--1933-1945.
National socialism--Germany--Hamburg.
Runoff--Germany--Hamburg--History--20th century.
Water-supply--Germany--Hamburg--History--20th century.
Waterworks--Germany--Hamburg--History--20th century.