1. Fossil Fuels, Explainedhttps://www.nationalgeographic.com/environment/energy/reference/fossil-fuels/
2. Oil Demand To Peak In Three Years, Says Energy Adviser DNV GLhttps://www.reuters.com/article/us-oil-demand-dnv-gl/oil-demand-to-peak-in-three-years-says-energy-adviser-dnv-gl-idUSKCN1VV2UQ
3. Air Pollution Costs Global Economy Trillions Annually, World Bank Sayshttps://time.com/4484027/air-pollution-economic-toll-world-bank/
4. Fuel Cell History—Fuel Cell Todayhttp://www.fuelcelltoday.com/history#Contents
5. The hybrid model of the new hydrogen combustion engine as the most efficient powertrain of tomorrow;Korn,2019