Columbia subject headings:
Harvard subject headings:
Poland. Urząd Bezpieczeństwa.
Political persecution--Poland--Białystok (Voivodeship)
Princeton subject headings:
Białystok (Poland)--History--20th century.
Church and state--Poland--Białystok--History--20th century.
Internal security--Poland--Białystok--History--20th century.
Poland--Politics and government--1945-1980.
Poland. Urząd Bezpieczeństwa