Text and Data Mining valid from 2019-03-18
Received: 25 September 2018
Accepted: 7 January 2019
First Online: 18 March 2019
Ethics approval and consent to participate
: The study protocol was approved by the institutional review board of Semmelweis University of Budapest. Informed consent was obtained from the participants in accordance with the Declaration of Helsinki.
: Not applicable.
: The authors declare that they have no competing interests.
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