Text and Data Mining valid from 2018-08-29
Received: 9 May 2018
Accepted: 23 August 2018
First Online: 29 August 2018
Ethics approval and consent to participate
: The study follows the Declaration of Helsinki and was approved by the ethics committee at Bielefeld University (study ID: 2014–135). All participants provided written informed consent before participating.
: Not applicable.
: The authors declare that they have no competing interests.
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