Text and Data Mining valid from 2019-10-31
Received: 23 July 2019
Accepted: 11 October 2019
First Online: 31 October 2019
Ethics approval and consent to participate
: This study was approved by the Institutional Review Board of the University of Occupational and Environmental Health, School of Medicine. All examiners provided informed consent for participation in this study.
: Not applicable.
: The authors declare that they have no competing interests.