1. Aer Lingus. Gold Circle. Availabe on line at: http://www.aerlingus.com/goldcircle/abouttheclub/[March 2013].
2. Air France. Flying Blue Clubs. Availabe on line at: http://www.airfrance.com/X08/en/local/voyageurfrequent/flyingblue/fblue_clubs.htm [March 2013].
3. Air France. Flying Blue Petrolum. Availabe on line at://www.airfrance.com/IN/en/common/voyageurfrequent/petroleumclub/petroleum_ligne_petroliere.htm [March 2013].
4. Air France. Voyageur Rewards. Points accumulation for Voyageur Rewards program. Availabe on line at: http://www.airfrance.com/HR/en/local/avotreservice/entreprises/rewards_gagner_bareme_point.htm [March 2013].
5. American Airlines AAdvantage. Program information. Availabe on line at:https://www.aa.com/i18n/AAdvantage/programInformation/main.jsp [March 2013].