Columbia subject headings:
Atto, Bishop of Vercelli, -961. Perpendiculum.
Italy--History--Period of the Italian Kings, 887-962.
Harvard subject headings:
Atto, Bishop of Vercelli, 924-961. Perpendiculum.
Italy--History--Period of the Italian Kings, 887-962.
Princeton subject headings:
Atto, Bishop of Vercelli, 924-961. Perpendiculum.
Italy--History--Period of the Italian Kings, 887-962.