Text and Data Mining valid from 2020-01-31
Received: 29 August 2019
Accepted: 6 January 2020
First Online: 31 January 2020
Ethics approval and consent to participate
: Ethical and judicial conformity of this study were attested and approved by the governmental research ethics committee (KEK ZH 2018–00711), and all participant and / or their legal guardians gave their written informed consent.
: Not applicable.
: The authors declare that they have no competing interests.