Franken, Lars
Klein, Marika
Spasova, Marina
Elsukova, Anna
Wiedwald, Ulf
Welz, Meike
Knolle, Percy
Farle, Michael
Limmer, Andreas
Kurts, Christian
Article History
Received: 6 January 2015
Accepted: 7 May 2015
First Online: 11 August 2015
Competing interests
: The authors declare no competing financial interests.