Text and Data Mining valid from 2019-09-11
Received: 26 May 2019
Accepted: 14 August 2019
First Online: 11 September 2019
Compliance with ethical standards
: On behalf of all authors, the corresponding author states that there is 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.