Columbia subject headings:
Convict labor--Soviet Union.
Correctional law--Soviet Union.
Prisoners--Legal status, laws, etc.--Soviet Union.
Prisons--Law and legislation--Soviet Union.
Harvard subject headings:
Convict labor--Soviet Union.
Correctional law--Soviet Union.
Criminals--Rehabilitation--Soviet Union
Prisoners--Legal status, laws, etc.--Soviet Union.
Princeton subject headings: