Columbia subject headings:
Anonymous letters--Italy--Venice.
Informers--Italy--Venice.
Venice (Italy)--History--1508-1797.
Harvard subject headings:
Criminal justice, Administration of--Italy--Venice--History.
Denunciation (Criminal law)--Italy--Venice--History.
Informers--Italy--Venice--History.
Princeton subject headings:
Criminal justice, Administration of--Italy--Venice--History.
Informers--Italy--Venice--History.