Text and Data Mining valid from 2019-04-29
Received: 22 December 2018
Accepted: 11 April 2019
First Online: 29 April 2019
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: The study was performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments. Ethical approval was given by the ethics committee of Goethe University Frankfurt (File number: 343/16).
: Not applicable.
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