Columbia subject headings:
Netherlands--Politics and government--20th century.
Reclamation of land--Netherlands--IJssel Lake Polders.
Reclamation of land--Netherlands--Lauwerszee.
Harvard subject headings:
Netherlands--Politics and government--20th century.
Reclamation of land--Netherlands--IJssel Lake Polders.
Reclamation of land--Netherlands--Lauwerszee.
Princeton subject headings: