Columbia subject headings:
Iron industry and trade--Wales, South--History--18th century.
Iron industry and trade--Wales, South--History--19th century.
Harvard subject headings:
Iron industry and trade--Wales, South--History--18th century.
Iron industry and trade--Wales, South--History--19th century.
Princeton subject headings:
Iron industry and trade--Wales, South--History--18th century.
Iron industry and trade--Wales, South--History--19th century.