Li, Lixiang http://orcid.org/0000-0001-9949-8731
Xu, Dafei
Peng, Haipeng
Kurths, Jürgen
Yang, Yixian
Article History
Received: 5 June 2017
Accepted: 23 October 2017
First Online: 8 November 2017
Competing Interests
: The authors declare that they have no competing interests.