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