Text and Data Mining valid from 2019-09-02
Received: 28 March 2019
Accepted: 26 August 2019
First Online: 2 September 2019
Ethics approval and consent to participate
: The study was conducted in accordance with the requirements of the declarations of Helsinki. All participants were informed about the procedures and signed an informed consent form prior to enrollment in the study.
: Not applicable.
: The authors declare that they have no competing interests.