Information on Driving in Italy
http://www.slowtrav.com/italy/driving/traffic_cameras_speeding.htm
5 Easy Ways to Get a Traffic Ticket in Italy
http://www.italybeyondtheobvious.com/dont-mess-with-ztl-zones
One Traveler's Horror Story
http://www.fodors.com/community/europe/italy-ztl-am-i-in-for-a-gigantic-hassle.cfm
Renting a Car in Italy? Do You Know What a ZTL Is?
https://community.ricksteves.com/travel-forum/transportation/renting-a-car-do-you-know-what-a-ztl-is