Ramalingam, Nagendran
Franke, Christof
Jaschinski, Evelin
Winterhoff, Moritz
Lu, Yao
Brühmann, Stefan
Junemann, Alexander
Meier, Helena
Noegel, Angelika A.
Weber, Igor
Zhao, Hongxia
Merkel, Rudolf
Schleicher, Michael
Faix, Jan
Article History
Received: 27 March 2015
Accepted: 27 August 2015
First Online: 29 September 2015
Competing interests
: The authors declare no competing financial interests.