1. 1 UK Civil Aviation Authority. UK Airport Statistics: 2003-Annual.[Accessed 20 Jun 2004.] Available from URL: http://www.caa.co.uk/erg/erg_stats/sgl.asp?sglid=3fld=2003Annual
2. 2 EH Hunt, DH Reid, DR Space, and FE. Tilton Commercial Airliner Environmental Control System Engineering. Aspects of Cabin Air Quality.[Accessed 16 Oct 2006.] Available from URL: http://www.boeing.com/commercial/cabinair/ecs.pdf
3. "Is there a doctor on the aircraft?" Top 10 in-flight medical emergencies