Columbia subject headings:
Harvard subject headings:
Flags of convenience--Congresses.
Flags of convenience--Germany (West)
Flags of convenience.
Ships--Germany (West)--Nationality--Congresses.
Ships--Nationality--Congresses.
Ships--Registration and transfer
Ships--Registration and transfer--Congresses.
Ships--Registration and transfer--Germany (West)
Princeton subject headings:
Flags of convenience--Germany (West).
Flags of convenience.
Ships--Registration and transfer--Germany (West).
Ships--Registration and transfer.