Columbia subject headings:
Harvard subject headings:
Forced labor--Germany--History--20th
Forced labor--Germany--History--20th century
Steel industry and trade--Germany--History
Steel industry and trade--Germany--History--20th century.
Thyssen & Co. (Mülheim an der Ruhr, Germany)--History--20th century.
Thyssen & Co. (Mülheim an der Ruhr, Germany)--History.
Thyssen & Co. (Mülhheim an der Ruhr, Germany)--History--20th century.
World War, 1939-1945--Conscript labor--Germany.
Princeton subject headings:
Forced labor--Germany--History--20th.
Steel industry and trade--Germany--History--20th century.
Thyssen & Co. (Mülhheim an der Ruhr, Germany)--History--20th century.
World War, 1939-1945--Conscript labor--Germany.