Columbia subject headings:
Harvard subject headings:
Deutsche Erd- und Steinwerke.
Gusen (Concentration camp)--History.
Mauthausen (Concentration camp)--History.
Underground factories--Austria--Sankt Georgen an der Gusen--History.
World War, 1939-1945--Prisoners and prisons, German.
Princeton subject headings:
Deutsche Erd- und Steinwerke.
Gusen (Concentration camp)--History.
Mauthausen (Concentration camp)
Sankt Georgen an der Gusen (Austria)--History.
Underground factories--Austria--Sankt Georgen an der Gusen.
World War, 1939-1945--Prisoners and prisons, German.