Text and Data Mining valid from 2019-04-06
Received: 30 January 2019
Accepted: 30 March 2019
First Online: 6 April 2019
Compliance with ethical standards
: The authors declare that they have no competing interests.
: All procedures performed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1964 and later versions.
: Informed consent was obtained from all individual participants included in the study.