Text and Data Mining valid from 2019-04-02
Received: 15 March 2019
Accepted: 26 March 2019
First Online: 2 April 2019
Compliance with ethical standards
: The author declares no conflict of interest.
: Approval from institutional board was not required for this communication.
: This article does not contain any studies with human participants or animals.
: For this retrospective review formal consent is not required.