Dai, Song
Li, Qiongling http://orcid.org/0000-0003-1487-0763
Funding for this research was provided by:
Division of Mathematical Sciences (1107452, 1107263)
Division of Mathematical Sciences (1107367)
Danmarks Grundforskningsfond (95)
National Natural Science Foundation of China (11601369)
Article History
Received: 19 February 2018
Revised: 5 September 2018
First Online: 15 November 2018