Text and Data Mining valid from 2018-09-14
Received: 20 April 2018
Accepted: 3 September 2018
First Online: 14 September 2018
Ethics approval and consent to participate
: In accordance with German legal regulations (§ 15 MBO-Ä), an ethics approval was not required for this study, as only routinely collected anonymised secondary data was analysed.
: Not applicable.
: The authors declare that they have no competing interests.
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