1. Airbus. Global market forecast 2007–2026. Airbus; 2007.
2. Boeing. Current market outlook 2008–2027. Boeing Commercial Airplanes; 2008.
3. Rolls Royce. Market outlook 2007—forecast 2007–2026. Rolls Royce plc.; 2007.
4. Boeing. Boeing commercial airplanes current product overview. San Diego: County Regional Airport Authority Advisory Committee; July 12, 2007.
5. Reduced environmental impact by lowering cruise altitude for liquid hydrogen fuelled aircraft;Sevensson;Aerospace Science and Technology,2004