Text and Data Mining valid from 2018-06-30
Received: 16 March 2018
Accepted: 9 June 2018
First Online: 30 June 2018
Compliance with ethical standards
: Informed consent was obtained from all individual participants included in the study. Additional informed consent was obtained from all individual participants for whom identifying information is included in this article.
: The author declares that he has no competing interests.