Text and Data Mining valid from 2020-04-30
Received: 20 December 2019
Accepted: 20 April 2020
First Online: 30 April 2020
Ethics approval and consent to participate
: This study was approved by the Korea University Institutional Review Board (Ref: 2019AS0273) and complied with the ethical standards of the relevant national and institutional committees on human experimentation and with the Helsinki Declaration of 1975, as revised in 2008. All participants provided written informed consent before their enrollment in the survey.
: Not applicable.
: The authors declare no competing interests.