Text and Data Mining valid from 2019-05-22
Received: 22 September 2017
Accepted: 8 May 2019
First Online: 22 May 2019
Ethics approval and consent to participate
: This study was approved by the ethical review board of Universidad Alfonso X Madrid UAX 2016–021 and written consent was obtained from all participants.
: Not applicable.
: The authors declare that they have no competing interest.
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