Liu, B.-H.
Wißmann, S.
Hu, X.-M.
Zhang, C.
Huang, Y.-F.
Li, C.-F.
Guo, G.-C.
Karlsson, A.
Piilo, J.
Breuer, H.-P.
Article History
Received: 2 June 2014
Accepted: 14 August 2014
First Online: 11 September 2014
Competing interests
: The authors declare no competing financial interests.