Text and Data Mining valid from 2018-11-13
Received: 1 September 2018
Accepted: 24 October 2018
First Online: 13 November 2018
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: This study has been approved by our Institution’s Ethics Committee and has therefore been performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments.