Chen, Zhen-Qing
Ren, Yan-Xia
Yang, Ting
Funding for this research was provided by:
Division of Mathematical Sciences (1206276)
National Natural Science Foundation of China (11128101)
National Natural Science Foundation of China (11128101)
National Natural Science Foundation of China (11501029)
Beijing Institute of Technology (Research Fund Program for Young Scholars)
Article History
Received: 19 March 2015
Accepted: 23 March 2016
First Online: 2 April 2016