Submitted on: 19 September 2014.
Revised on: 06 November 2014.
Accepted on: 20 November 2014.
___________________BMC Pediatrics---BMC
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Submitted on: 10 December 2017.
Revised on: 09 April 2018.
Accepted on: 16 May 2018.
___________________BMC Pediatrics---BMC
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