Columbia subject headings:
Harvard subject headings:
Middle Ages--Congresses
Water mills--Europe, Central--History--To 1500--Congresses.
Water use--Europe, Central--History--To 1500--Congresses.
Princeton subject headings:
Water mills--Europe--History--To 1500--Congresses.
Water use--Europe, Central--History--To 1500--Congresses.
Water-supply--Europe, Central--History--To 1500--Congresses.
Water-wheels--Europe--History--To 1500--Congresses.