Columbia subject headings:
Assassins--Italy--Palermo--History.
Giacosa, Guido.
Terrorism--Italy--Palermo--History.
Trigona, Romualdo, 1809-
Harvard subject headings:
Assassins--Italy--Palermo--History.
Giacosa, Guido.
Terrorism--Italy--Palermo--History.
Trigona, Romualdo, 1809-
Princeton subject headings:
Assassins--Italy--Palermo--History.
Giacosa, Guido.
Terrorism--Italy--Palermo--History.
Trigona, Romualdo, 1809-