Xu, X http://orcid.org/0000-0002-9780-1570
Su, S
Wang, X
Barnes, V
De Miguel, C
Ownby, D
Pollock, J
Snieder, H
Chen, W
Wang, X
Article History
Received: 6 May 2014
Revised: 30 September 2014
Accepted: 13 October 2014
First Online: 12 November 2014
Competing interests
: The authors declare no conflict of interest.