Gudbrandsen, O A
Kodama, Y
Mjøs, S A
Zhao, C-M
Johannessen, H
Brattbakk, H-R
Haugen, C
Kulseng, B
Mellgren, G
Chen, D
Article History
Received: 15 April 2014
Accepted: 10 May 2014
First Online: 30 June 2014
Competing interests
: The authors declare no conflict of interest.