Text and Data Mining valid from 2018-04-16
Received: 29 June 2017
Accepted: 27 March 2018
First Online: 16 April 2018
Ethics approval and consent to participate
: This study was conducted according to the declaration of Helsinki and had ethical approval from Institutional Review Board at the Gyeongsang National University. All subjects gave written informed consent prior to data collection.
: Participants gave written informed consent to data treatment in this research study and permission to publish anonymous data and results.
: The authors declare that they have no competing interests.
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