1. Emergency Health Services; Department of Emergency Medicine and Community Health and Epidemiology; Nova Scotia Canada
2. St George's, University of London; Population Health Sciences and Education; London UK
3. c/o Cochrane Airways Group; London UK
4. Massachusetts General Hospital; Department of Emergency Medicine; 326 Cambridge St, Suite 410 Boston Massachusetts USA 02114
5. University of Alberta; Department of Emergency Medicine; Room 1G1.43 Walter C. Mackenzie Health Sciences Centre 8440 112th Street Edmonton Alberta Canada T6G 2B7
6. University of Alberta; School of Public Heath; Edmonton Canada