Funding for this research was provided by:
Text and Data Mining valid from 2019-11-08
Received: 17 February 2019
Accepted: 20 October 2019
First Online: 8 November 2019
Ethics approval and consent to participate
: This study was approved by the Institutional Review Board of Keimyung University (No. 40525–201712-BR-93-02). We obtained written informed consent from each participant. Participation was voluntary, and the participants could withdraw from the study at any time.
: Not applicable.
: The authors declare no competing interest.