Columbia subject headings:
Basse-Normandie (France)--Economic conditions.
Coal mines and mining--France--Basse-Normandie--History.
Iron mines and mining--France--Basse-Normandie--History.
Mineral industries--France--Basse-Normandie--History.
Miners--France--Basse-Normandie--History.
Harvard subject headings:
Basse-Normandie (France)--Economic conditions.
Basse-Normandie (France)--Social conditions.
Mineral industries--France--Basse-Normandie--History.
Miners--France--Basse-Normandie--History.
Mines and mineral resources--France--Basse-Normandie--History.
Princeton subject headings: