Columbia subject headings:
Harvard subject headings:
Communism.
Internal security--Europe, Central--History.
Internal security--Europe, Eastern--History.
Internal security--Soviet Union--History
Political persecution.
Secret service--Europe, Central--History.
Secret service--Europe, Eastern--History.
Secret service--Soviet Union--History
Princeton subject headings:
Communism.
Internal security--Europe, Central--History.
Internal security--Europe, Eastern--History.
Internal security--Soviet Union--History.
Political persecution.
Secret service--Europe, Central--History.
Secret service--Europe, Eastern--History.
Secret service--Soviet Union--History.