Text and Data Mining valid from 2019-05-15
Received: 17 December 2018
Accepted: 7 May 2019
First Online: 15 May 2019
Compliance with ethical standards
: The authors declare that there is no conflict of interest that could prejudice the impartiality of the article.
: All procedures performed were in accordance with the ethical standards of the institution and with the 1964 Helsinki Declaration and its later amendments.
: Informed consent is not required.