Columbia subject headings:
Harvard subject headings:
Contracting out--Germany (East)--History--20th century.
Contracting out--Germany (East)--History--21st century.
Mineral industries--Germany (East)--Employees--History--20th century.
Mineral industries--Germany (East)--Employees--History--21st century.
Mineral industries--Germany (East)--History--20th century.
Mineral industries--Germany (East)--History--21st century.
Princeton subject headings:
Contracting out--Germany (East)--History--20th century.
Contracting out--Germany (East)--History--21st century.
Mineral industries--Germany (East)--Employees--History--20th century.
Mineral industries--Germany (East)--Employees--History--21st century.
Mineral industries--Germany (East)--History--20th century.
Mineral industries--Germany (East)--History--21st century.