1. National Ski Patrol. NSP background and evolution. Available at: http://www.Nsp.Org/about/background.Aspx. Accessed February 28, 2014.
2. National Association of State EMS Officials — Medical Director’s Council. The definition of EMS. Available at: https://http://www.Nasemso.Org/councils/medicaldirectors/documents/definition-of-ems-2012.Pdf. Accessed September 8, 2016.
3. Accidental death and disability: The neglected disease of modern society,1966
4. The formation of the emergency medical services system;Shah;Am J Public Health,2006
5. Wilderness EMS;Hawkins,2010