Yu, J
Wu, W K K
Liang, Q
Zhang, N
He, J
Li, X
Zhang, X
Xu, L
Chan, M T V
Ng, S S M
Sung, J J Y
Article History
Received: 22 October 2014
Revised: 29 December 2014
Accepted: 6 January 2015
First Online: 30 March 2015
Competing interests
: The authors declare no conflict of interest.