1. Mathematics Department Keele University Keele Staffordshire United Kingdom
2. Department of Anaesthesiology Division of Emergencies and Critical Care Oslo University Hospital Ullevål Oslo Norway
3. Oslo University Hospital Trauma Registry Division of Emergencies and Critical Care Oslo University Hospital Ullevål Oslo Norway
4. Department of Anaesthesia and Critical Care Akershus University Hospital Lørenskog Norway
5. Institute of Clinical Medicine Faculty of Medicine University of Oslo Oslo Norway
6. Department of Research and Development Norwegian Air Ambulance Foundation Drøbak Norway