Text and Data Mining valid from 2018-07-03
Received: 22 May 2016
Accepted: 23 April 2018
First Online: 3 July 2018
Ethics approval and consent to participate
: This study was approved by the Institutional Review Boards of Korea University Medical Center (KUGH16339). The IRB waived the requirements to obtain informed consent.
: The authors declare that they have no competing interests.
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