Columbia subject headings:
Kommunisticheskai͡a partii͡a Sovetskogo Soi͡uza--Purges--History.
Political purges--Soviet Union--History--20th century.
Soviet Union--Politics and government--1936-1953.
Soviet Union. Narodnyĭ komissariat vnutrennikh del.
Harvard subject headings:
Political atrocities--Soviet Union.
Political persecution--Soviet Union.
Soviet Union--Politics and government--1936-1953.
Princeton subject headings:
Political atrocities--Soviet Union.
Political persecution--Soviet Union.
Soviet Union--Politics and government--1936-1953.