1. Policy statement—medical direction of emergency medical services;American College of Emergency Physicians;Ann Emerg Med,1998
2. The ambulance in American cities;Anonymous;JAMA,1987
3. Kowalski v. Gratopp 442 N.W.2d 682 1989.
4. Highway Safety Program Standard Number 11: Emergency Medical Services.23 CFR 1205.4 November 14 1968.