1. Air Transport, Passengers Carried. Data from the World Bank. Published 2019. Accessed 25 Jun 2020. https://data.worldbank.org/indicator/IS.AIR.PSGR
2. Industry Statistics Fact Sheet. International Air Transport Association. Published June 2019. Accessed 07 Oct 2020. https://www.iata.org/en/iata-repository/publications/economic-reports/airline-industry-economic-performance—june-2019—data-tables/
3. Assessing Fitness to Fly: Guidance to Health Professionals. UK Civil Aviation Authority. Published 2015. Accessed 25 Jun 2020. https://www.caa.co.uk/passengers/before-you-fly/am-i-fit-to-fly/guidance-for-health-professionals/assessing-fitness-to-fly/
4. Medical advice for commercial air travellers;Bettes;Am Fam Physician,1999
5. Aerospace Medical Association (AsMA) Medical Considerations for Air Travel. Published 2020. Accessed 7 Oct 2020. http://www.asma.org/publications/medical-publications-for-airline-travel/medical-considerations-for-airline-travel