Guo, Hailong
Zhang, Zhimin
Zou, Qingsong
Funding for this research was provided by:
National Natural Science Foundation of China (11571384, 11428103)
Division of Mathematical Sciences (1419040)
National Natural Science Foundation of China (11471031, 91430216)
Article History
Received: 8 December 2016
Revised: 29 June 2017
Accepted: 11 July 2017
First Online: 20 July 2017