Columbia subject headings:
GULag NKVD.
Internment camps--Soviet Union--History.
Nazi concentration camps--Soviet Union--History.
Political persecution--Soviet Union.
Harvard subject headings:
GULag NKVD.
Internment camps--Soviet Union--History
Political persecution--Soviet Union.
Princeton subject headings:
GULag NKVD.
Internment camps--Soviet Union--History.
Political persecution--Soviet Union.