Columbia subject headings:
Harvard subject headings:
Dikes (Engineering)--Germany--History.
Shore protection--Germany--History.
Princeton subject headings:
Dikes (Engineering)--Denmark--History.
Dikes (Engineering)--Germany--History.
Dikes (Engineering)--North Sea Region--History.
Dikes (Geology)--Denmark--History.
Dikes (Geology)--Germany--History.
Dikes (Geology)--North Sea Region--History.
Reclamation of land--Denmark--History.
Reclamation of land--Germany--History.
Reclamation of land--North Sea Region--History.