Liu, Kun
He, Le
Li, Shiwei
Tian, Fengshou
Sun, Zhongke
Li, Chengwei http://orcid.org/0000-0001-6977-8273
Funding for this research was provided by:
Zhoukou Normal University (ZKNU2015107)
the Education Department of Henan Province (17A180017)
Article History
Received: 14 November 2017
Accepted: 8 December 2017
First Online: 19 January 2018
Compliance with ethical standards
:
: We declare no conflict of interest with respect to this paper.