Funding for this research was provided by:
the Kunming Science and Technology Bureau (grant no. 2016-2-S-06890)
Text and Data Mining valid from 2019-11-13
Received: 22 February 2019
Accepted: 16 October 2019
First Online: 13 November 2019
Ethics approval and consent to participate
: The formal ethical approval of this systematic review is not applicable because it’s a secondary analysis based on literature.
: Not applicable.
: All authors declare that they have no competing interest.