Ticket Information" . Emaar Properties . http://www.burjkhalifa.ae/observation-deck/ticket-information.aspx . Retrieved 9 February 2010 .   ^ "Emaar Says Burj Khalifa Observation Deck Closed for Maintenance" . Bloomberg . 8 February 2010 . http://www.businessweek.com/news/2010-02-08/emaar-says-burj-khalifa-observation-deck-closed-for-maintenance.html . Retrieved 9 February 2010 .   ^ Tomlinson, Hugh (10 February 2010). "Terrifying lift ordeal at Burj Khalifa