Simon, Barry (2010). "Example 15.4.6 (Asymptotics of Bell Numbers)". Complex Analysis(PDF). pp. 772–774. Archived from the original(PDF) on 2014-01-24. Retrieved 2012-09-02.
Simon, Barry (2010). "Example 15.4.6 (Asymptotics of Bell Numbers)". Complex Analysis(PDF). pp. 772–774. Archived from the original(PDF) on 2014-01-24. Retrieved 2012-09-02.