Li, Hengguang
Zhang, Qinghui
Funding for this research was provided by:
National Science Foundation (DMS-1158839, DMS-1418853)
Natural Science Foundation of China (11001282, 11471343)
Guangdong Provincial Natural Science Foundation of China (2015A030306016)
Wayne State University
Article History
Received: 30 January 2015
Revised: 21 January 2016
Accepted: 24 June 2016
First Online: 4 July 2016