Columbia subject headings:
Harvard subject headings:
Industries--Germany--Münster in Westfalen--History--20th century.
Labor movement--Germany--Münster in Westfalen--History--20th century.
Metal trade--Germany--Münster in Westfalen--History--20th century.
Metal-workers--Germany--Münster in Westfalen--History--20th century.
Princeton subject headings:
Metal-workers--Germany--Münster--History--20th century.
Metal-workers--Labor unions--Germany--Münster--History--20th century.