Text and Data Mining valid from 2018-09-05
Received: 31 January 2018
Revised: 29 June 2018
Accepted: 2 August 2018
First Online: 5 September 2018
Compliance with ethical standards
: • The authors declare that they have no conflict of interest.
: • 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.