1. Airports Council International, 2005. Passenger Traffic 2004 (Final), http://www.aci.aero/cda/aci/display/main/aci_content.jsp?zn=aci&cp=1-5_9_2_.
2. Association of European Airlines, 2004. Summary of Traffic and Airlines Results, www.aea.be.
3. Aviation Environment Federation, 2001. From planes to trains: realising the potential from shifting short-haul flights to rail. Study Produced for Friends of the Earth.
4. The historical fuel efficiency characteristics of regional aircraft from technological, operational, and cost perspectives;Babikian;J. Air Transport Manage.,2002
5. Rail vs. air transport for medium range trips;Capon,2003