Text and Data Mining valid from 2018-05-31
Received: 15 December 2017
Accepted: 25 May 2018
First Online: 31 May 2018
Ethics approval and consent to participate
: This study was conducted in accordance with the Declaration of Helsinki, and the protocol was approved by the ethical committee of the Ruhr-University Bochum. All participants gave written informed consent prior to being enrolled in the study.
: The authors declare that they have no competing interests.
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