Calin, Ovidiu
Chang, Der-Chen
Hu, Jishan
Funding for this research was provided by:
National Science Foundation (DMS-1408839)
Research Grants Council, University Grants Committee (601813 and 601410)
Article History
Received: 17 October 2015
Revised: 2 February 2016
Accepted: 3 February 2016
First Online: 13 February 2016