Funding for this research was provided by:
Tübinger Profil (F7281048)
Text and Data Mining valid from 2019-05-28
Received: 21 March 2018
Accepted: 17 May 2019
First Online: 28 May 2019
Ethics approval and consent to participate
: The project was approved by the local ethics committee of the university of Tuebingen, number 667/2016BO2. All participants gave written consent and could withdraw study participation at any time without giving reasons.
: Not applicable.
: The authors declare that they have no competing interests.