Columbia subject headings:
Grinding machines--Germany--Zenn River Region--History.
Millers--Germany--Zenn River Region--Economic conditions.
Millers--Germany--Zenn River Region--Social life and customs.
Milling machinery--Germany--Zenn River Region--History.
Mills and mill-work--Germany--Zenn River Region--History.
Water mills--Germany--Zenn River Region--History.
Harvard subject headings:
Grinding machinery industry--Germany--Zenngrund--History.
Millers--Germany--Zenngrund--Economic conditions.
Millers--Germany--Zenngrund--Social life and customs.
Milling machinery--Germany--Zenngrund--History.
Mills and mill-work--Germany--Zenngrund--History.
Water mills--Germany--Zenngrund--History.
Princeton subject headings:
Grinding machinery--Germany--Zenngrund--History.
Millers--Germany--Zenngrund--Economic conditions.
Millers--Germany--Zenngrund--Social life and customs.
Milling machinery--Germany--Zenngrund--History.
Mills and mill-work--Germany--Zenngrund--History.
Water mills--Germany--Zenngrund--History.