Text and Data Mining valid from 2019-01-24
Received: 2 November 2018
Accepted: 2 January 2019
First Online: 24 January 2019
Compliance with ethical standards
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. For this type of study, formal consent is not required.