1. Airbus, 2013. Airbus launches sharklet retrofit for in-service A320 family aircraft: cuts fuel burn by up to 4%, lengthens in-service life. 〈http://www.airbus.com/presscentre/pressreleases/press-release-detail/detail/airbus-launches-sharklet-retrofit-for-in-service-a320-family-aircraft/〉. (Accessed 22 March 2017).
2. Airbus, 2017a. Global market forecast – growing horizons 2017/2035. 〈https://www.google.de/url?Sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0ahUKEwj7mJLb_KPVAhWPOsAKHSlRBsMQFggzMAE&url=http%3A%2F%2Fwww.airbus.com%2Fcontent%2Fdam%2Fcorporate-topics%2Fpublications%2Fbackgrounders%2FAirbus_Global_Market_Forecast_2017-2036_Growing_Horizons_full_book.pdf&usg=AFQjCNG5PDssDAMYi2×3DyVfKv_uaU6AlQ&cad=rja〉. (Accessed 25 July 2017).
3. Airbus, 2017b. Orders & deliveries. 〈http://www.airbus.com/company/market/orders-deliveries/〉. (Accessed 2 May 2017).
4. Our Aircraft Portfolio;Airbus,2017
5. Facts & Figures;ATAG,2017