Columbia subject headings:
Poland--History--1945-1980.
Poland--Politics and government--1945-1980.
Harvard subject headings:
Communist parties--Poland--History.
Opposition (Political science)--Poland--History--20th century.
Poland--Politics and government--1945-1980
Princeton subject headings:
Communist parties--Poland--History.
Opposition (Political science)--Poland--History--20th century.
Poland--Politics and government--1945-1980.