Text and Data Mining valid from 2019-04-06
Received: 25 January 2019
Accepted: 27 March 2019
First Online: 6 April 2019
Compliance with ethical standards
: None of the authors has direct or indirect commercial financial incentive associated with publishing the article and does not have any conflict of interest, and will sign the Disclosing Form.
: 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.
: Informed consent was obtained from all individual participants included in the study.