Text and Data Mining valid from 2018-12-01
Received: 7 August 2018
Accepted: 23 November 2018
First Online: 5 December 2018
Ethics approval and consent to participate
: The study was approved by the local ethics committee (n°5/2011, <i>A.O.U.P. “Paolo Giaccone”</i>, Palermo, Italy).
: Written informed consent was provided by parents of all participants.
: All authors declare that they have no competing interests.
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