Li, Shangshan
Luan, Jie http://orcid.org/0000-0002-8927-2648
Article History
Received: 6 July 2018
Accepted: 24 November 2018
First Online: 14 December 2018
Compliance with Ethical Standards
:
: The authors declare that they have no conflict of interest to disclose.
: All analyses were based on previous published studies, thus ethical approval is unnecessary.
: This study was based on previous published studies, thus informed consent was unnecessary.