Columbia subject headings:
Poland--Politics and government--1918-1945.
Socialism--Poland--History.
Socialist parties--Poland--History.
Harvard subject headings:
Poland--Politics and government--1918-1945
Socialism--Poland
Socialism--Poland--History
Socialist parties--Poland--History.
Princeton subject headings:
PPS-Lewica--History.
Polska Partia Socjalistyczna--History.
Socialism--Poland--History.