Columbia subject headings:
Harvard subject headings:
Dueling--Germany--History--To 1500--Congresses.
Feudalism--Germany--History--To 1500--Congresses.
Nobility--Germany--History--To 1500--Congresses.
Vendetta--Germany--History--To 1500--Congresses.
Vendetta--Social aspects--Germany--History--To 1500--Congresses.
Princeton subject headings:
Feudalism--Germany--History--To 1500--Congresses.
Nobility--Germany--History--To 1500--Congresses.
Vendetta--Germany--History--To 1500--Congresses.