Columbia subject headings:
Harvard subject headings:
Drinking water--Germany (East)--History.
Sewage--Purification--Germany (East)--History.
Water resources development--Germany (East)--History.
Water--Storage--Germany (East)--History.
Water-supply--Germany (East)--Management--History.
Waterworks--Germany (East)--History.
Princeton subject headings:
Drinking water--Germany (East)--History.
Sewage--Purification--Germany (East)--History.
Water resources development--Germany (East)--History.
Water--Storage--Germany (East)--History.
Water-supply--Germany (East)--Management--History.
Waterworks--Germany (East)--History.