Text and Data Mining valid from 2019-05-10
Received: 28 December 2017
Accepted: 26 April 2019
First Online: 10 May 2019
Ethics approval and consent to participate
: The study was approved by the Research Ethics Committee of the Universidad de Sevilla (2013/07/11). Written informed consent was obtained from legal parent or guardian for children.
: Not applicable.
: The authors declare that they have no competing interests.
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