Text and Data Mining valid from 2019-01-08
Received: 25 October 2018
Accepted: 20 December 2018
First Online: 8 January 2019
Compliance with ethical standards
: The author declares no conflict of interest in relation to the present work.
: Patients have not been involved in relation to this work.
: No experiments have been performed involving humans or animals in relation to this work.