Columbia subject headings:
Italy--History--Germanic rule, 962-1268--Sources.
Pietro, della Gazzata, 1336 or 1337-1414.
Reggio Emilia (Italy)--History--Sources.
Harvard subject headings:
Italy--History--Germanic rule, 962-1268--Sources.
Pietro, della Gazzata, -1414.
Reggio Emilia (Italy)--History--Sources.
Princeton subject headings:
Italy--History--Germanic rule, 962-1268--Sources.
Pietro, della Gazzata, 1336 or 1337-1414.
Reggio Emilia (Italy)--History--Sources.