Chen, Weitao
Chou, Ching-Shan
Kao, Chiu-Yen
Funding for this research was provided by:
National Science Foundation (DMS1318364, DMS1253481)
Article History
Received: 15 October 2015
Revised: 23 March 2016
Accepted: 9 May 2016
First Online: 24 May 2016