Article History
Received: 18 June 2019
Accepted: 25 June 2019
First Online: 15 July 2019
Compliance with Ethical Standards
:
: The authors declare that they have no conflict of interest.
: Because the research is a literature review, obtaining approval of an ethical committee was not necessary.
: This research is a literature review, so these statements are not applicable.
: This research is a literature review, so these statements are not applicable.