Funding for this research was provided by:
Text and Data Mining valid from 2020-05-04
Received: 22 August 2019
Accepted: 22 April 2020
First Online: 4 May 2020
Ethics approval and consent to participate
: All participants were invited to participate voluntarily by an email that contained a brief introduction of the study and a link to the online survey form (Google form). The anonymity of the participants was guaranteed. Ethical approval for the study was given by the Institutional Review Board of the Hanoi Medical University (Decision No 174/HMU-IRB).
: Not applicable.
: The authors declare that they have no competing interests.