1. Boeing, http://www.boeing.com [Last accessed February 2015].
2. Enviro, http://www.enviro.aero/Content/Upload/File/BeginnersGuide_Biofuels_Web [Last accessed February 2015].
3. IATA, http://www.boeing.com/commercial/cmo/forecast_summary.html [Last accessed February 2015].
4. System for assessing aviation's global emissions (SAGE), part 2: uncertainty assessment;Lee;Transp Res DTRE,2007
5. USHP, http://www.house.gov/transportation/aviation/02-15-06/02-15-06memo.html [Last accessed May 2015].