Nilsson, H
Lindgren, D
Mandahl Forsberg, A
Mulder, H
Axelson, H
Johansson, M E
Article History
Received: 7 July 2014
Revised: 13 November 2014
Accepted: 17 November 2014
First Online: 8 January 2015
Competing interests
: The authors declare no conflict of interests.