1. Brain Injury Association of America. About brain injury. http://www.biausa.org/about-brain-injury.htm . Accessed 14 Feb 2017.
2. World Health Organization. Projections of mortality and burden of disease, 2002–2030: deaths by income group. http://www.who.int/healthinfo/global_burden_disease/projections2002/en/ . Accessed 14 Feb 2017.
3. World Economic Forum. The global economic burden of non-communicable diseases. 2011. http://www3.weforum.org/docs/WEF_Harvard_HE_GlobalEconomicBurdenNonCommunicableDiseases_2011.Pdf . Assessed 31 Jan 2017.
4. Masel BE, DeWitt DS. Traumatic brain injury: a disease process, not an event. J Neurotrauma. 2010;27(8):1529–40.
5. Feinstein AR. The pre-therapeutic classification of co-morbidity in chronic disease. J Chronic Dis. 1970;23:455–68.