Columbia subject headings:
Harvard subject headings:
Democracy--History--20th century
Depressions--1929--Netherlands.
Netherlands--Politics and government--1898-1948.
Sociaal-democratische Arbeiders-Partij--History.
Socialism--Belgium--20th century.
Socialism--Belgium--History--20th century.
Socialism--Netherlands
Princeton subject headings:
Socialism--Netherlands--History--20th century.