Columbia subject headings:
Harvard subject headings:
Internment camps--Soviet Union--History
Nazi concentration camps--Germany--History
Prisons--Germany--History--20th century.
Prisons--Soviet Union--History--20th century.
Princeton subject headings:
Internment camps--Soviet Union--History--20th century.
Nazi concentration camps--Germany.
Prisons--Germany--History--20th century.
Prisons--Soviet Union--History--20th century.