Columbia subject headings:
Norway--History--To 1030.
Norway--Kings and rulers--Biography.
Olav I Trygveson, King of Norway, 968-1000.
Harvard subject headings:
Norway--History--To 1030
Norway--Kings and rulers--Biography.
Olav I Trygveson, King of Norway, 968-1000
Princeton subject headings:
Norway--History--To 1030.
Norway--Kings and rulers--Biography.
Olav I Trygveson, King of Norway, 968-1000.